Every digital tachograph in the EU speaks the same visual language. Whether you drive a 7.5-tonne lorry across Bavaria or a 40-tonne articulated truck from Rotterdam to Athens, the symbols on your tachograph display follow a single, legally-binding standard set by Regulation (EU) 2016/799, Annex I C — the technical specification for smart tachographs.
But understanding the icons is only half the job. The same screen that shows your activity also displays warnings, events, faults, and manufacturer-specific pop-up messages — and getting them wrong can cost a driver a fine, force a vehicle off the road, or trigger a mandatory workshop visit within seven days. This guide walks through every category, with verified messages drawn from the official manuals of the four most widely fitted units in Europe: VDO DTCO 4.1, Stoneridge SE5000, Actia SmarTach and EFAS-4.
- Four activity symbols every driver must know
- Universal warning categories (events, faults, time, notes)
- 200+ verified codes & symbols (searchable)
- Top 10 most common tachograph messages in practice
- Critical-error workflow: what to do roadside
- Official sources & manufacturer manuals
- FAQ — symbols and error codes
Four activity symbols every driver must know
Every digital tachograph records driver time under one of four categories, each shown by a single ISO-2575 pictogram on the display. These are not just visual labels — they are legally distinct categories under EC Regulation 561/2006 (drivers' hours) and Directive 2002/15/EC (working time for mobile workers), and they determine how your day counts toward driving limits, breaks, and rest periods.
Driving (steering wheel)
Set automatically the moment the vehicle moves. Cannot be changed by hand. Counts toward your 4½-hour continuous limit, 9/10-hour daily, and 56/90-hour weekly/fortnightly driving limits.
Other work (crossed hammers)
All paid work that is not driving: loading and unloading, fuelling, paperwork, vehicle checks, helping passengers. Counts as working time under the WTD. Does not count as a break.
Availability (square diamond)
Waiting time whose duration is known in advance: ferry/train, queueing at a customer, accompanying a vehicle being towed. Period of availability does not count as a break under drivers' hours, but does count toward working time under the WTD.
Break / rest (bed)
Genuine break or daily/weekly rest. The driver must do no work and be free to dispose of their time. The only category that resets the 4½-hour continuous-driving clock and counts toward the mandatory 11-hour daily rest.
The selector buttons on the unit (Driver 1 / Driver 2) let you switch between Other work, Availability and Break/rest. Driving is always set automatically by the motion sensor — if you see Driving while the vehicle is stationary, the tachograph is recording a fault, not an activity (more on this below). Common driver errors with these four symbols — and why "Availability" can never legally replace a break — are covered in section 4.
Universal warning categories every tachograph uses
Once you move past the four activity symbols, all warning messages displayed by digital tachographs fall into one of four families. The VDO DTCO 4.1 manual calls these out explicitly (page 109), and the same logic is followed by Stoneridge SE5000, Actia SmarTach and EFAS-4 — because Annex I C defines the categories at the regulation level. Knowing which family a message belongs to tells you immediately how serious it is and whether you can continue your shift.
! Event
An operational occurrence recorded by the tachograph that is not necessarily a hardware failure — for example, driving without a valid card, exceeding the speed limit, or a card insertion while moving. Most events must be acknowledged with the OK button. The vehicle unit (VU) writes a record to mass memory and to the driver card.
x Fault
A genuine hardware or software malfunction: sensor fault, printer failure, internal time error, downloading fault, GNSS fault. Faults trigger the legal seven-day workshop rule — the unit must be inspected by an authorised workshop within one week. Driving with a known fault is permitted only with documented manual records.
↻ Driving-time warning
A compliance pre-warning: continuous driving approaching 4½ hours, daily/weekly driving time nearing its limit, or the next required rest is due. The flashing background light is the visual cue. These messages help you comply with Reg 561/2006 — they are not faults.
i Operational note
An informational prompt: "please enter", "no paper", "card error", "calibration due in 28 days". Operational notes appear without flashing and disappear automatically after a few seconds. No data is written to the mass memory; the message is purely a UI hint.
Every error message you will see — whether from a VDO DTCO 4.0, a Stoneridge SE5000 Exakt Duo², an Actia SmarTach or any other unit type-approved under Annex I C — belongs to exactly one of these four families. From this point in the guide we will look at each family in detail, with verified message text from the manufacturer manuals.
200+ verified error codes from four manufacturer manuals
The four most widely installed digital tachograph models in Europe are VDO DTCO 4.1 (Continental — the dominant unit in Central Europe and the Czech / Slovak market), Stoneridge SE5000 Exakt Duo² (the UK and Scandinavian default), Actia SmarTach (popular in France and southern Europe) and EFAS-4 (Intellic / Schneider, common in Germany and Poland). Each vendor uses a slightly different on-screen wording, but all conform to Annex I C — so the underlying meaning of an "internal fault", a "sensor fault" or a "card not closed" is identical regardless of the unit on your dashboard.
The codes below are taken directly from the official, publicly downloadable user manuals — file references are listed in the sources section. Where the manual gives an English wording, we use it verbatim; we have only added a plain-English "what to do" column where the manual leaves this to the driver's judgement.
VDO DTCO 4.1 / 4.1a / 4.1b
The VDO DTCO 4.1 family is the second-generation smart tachograph (Smart Tacho 2) and the most common unit on Czech, Slovak, German and Austrian fleets. The messages below are taken from VDO DTCO 4.1 Instruction Manual, Edition 3 / 2024-08, BA00.1381.41 100 102 (Continental Automotive Technologies GmbH). The official structure of messages is: Events (such as driving without a card), Faults (hardware malfunctions of the unit), Driving-time warnings and Operational notes.
Events — operational occurrences (highest priority)
| Message | Cause (from manual) | What to do | Severity |
|---|---|---|---|
| ! security breach xx | Error in the data memory; data security in the DTCO 4.1x is no longer ensured. The sensor data is no longer reliable. The DTCO housing was opened without authorisation. | Acknowledge message. The card is automatically ejected — even while driving. Reinsert it or have it checked in an authorised workshop. | Critical |
| !1 security breach xx | The card lock is disrupted or faulty. The DTCO no longer detects a tachograph card that was previously inserted correctly. Card identity, authenticity or stored data is unreliable. | Confirm message. Reinsert tachograph card or get it checked. | Critical |
| ! power interruption xx | The power was disconnected or the supply to the DTCO sensor was too low or too high. Can also be displayed when the engine is started. | Acknowledge message. If it reoccurs, check the vehicle's power supply. | Medium |
| x sensor fault | Communication with the motion sensor is interrupted. The message also appears after a voltage interruption. | Acknowledge message. If recurring, consult an authorised specialist workshop. | Critical |
| ! motion conflict xx | Contradiction in the evaluation of vehicle movement between the sensor and an independent signal source. The ferry/train function may not have been set during the shipping process. | Confirm message. Consult an authorised specialist workshop — possible manipulation or damage. | Critical |
| ! GNSS is missing xx | No position data over three hours of cumulative driving time. | Acknowledge message. Check that the GNSS antenna is not covered or obstructed. | Medium |
| !? GNSS anomaly | Manipulation detected or external attack on the GNSS signal (anti-spoofing OSNMA). | Check for manipulation reasons. Verify GNSS function. Replace defective components if needed. | High |
| ! time conflict xx | A difference of more than one minute between the DTCO's internal clock and the time received from the GNSS signal. | Acknowledge. Have an authorised workshop inspect and correct the tachograph if the issue persists. | Medium |
| ! DSRC comm. error xx | A communication error has occurred between the DTCO 4.1x and the external DSRC-CAN module (used for remote roadside checks). | Confirm message. If it reoccurs, consult an authorised specialist workshop. | Medium |
| ! driving without card xx | Driving commenced without a driver card — or without a valid driver card — in card drawer 1. Also triggered if an unauthorised card combination is inserted before or after the journey. | Stop the vehicle. Insert a valid driver card. Remove any company / control card from the DTCO first if needed. | High |
| !1 insertion while driving xx | The driver card was inserted after the vehicle had already started moving. | Acknowledge message. Plan card insertion before moving off in future. | Medium |
| !1 time overlap xx | The UTC time of this tachograph is behind the UTC time of the previous tachograph, producing a negative time difference (typical when changing vehicles). | Identify the tachograph with the incorrect UTC time and have an authorised workshop inspect and correct it. | Medium |
| !1 card not valid xx | The tachograph card has expired, is not yet valid, or its authentication has failed. A card that becomes invalid after midnight is automatically written to and ejected once the vehicle stops. | Confirm message. Check the tachograph card and reinsert; renew if expired. | Medium |
| ! cards conflict xx | The two tachograph cards must not be inserted together — for example a company card together with a control card. | Confirm message. Remove the conflicting card from the relevant drawer. | Medium |
| !1 card not closed xx | The driver card was not properly removed from the previous tachograph. Some driver-based data may not have been saved. | Acknowledge. From now on, always wait for the card to be released before pulling. | Medium |
| ⊃ overspeed xx | The configured maximum speed was exceeded for longer than 60 seconds. | Confirm message. Reduce speed. Repeated overspeed events are visible to enforcement on download. | High |
| § calibration in days ?? | The periodic two-yearly inspection of the tachograph is approaching (warning appears 28 days in advance). | Confirm. Book an appointment with an authorised workshop before the deadline. | Low |
| 1 download in days ?? | The next driver-card download is due (warning appears 14 days in advance). | Perform a download of the driver card before the deadline expires. | Low |
| 1 expires in days ?? | The driver card expires soon (typically warned 28 days in advance). | Confirm message. Apply to renew the card with your member state authority. | Info |
| ! end of normal operation in ?? | The DTCO 4.1x type-approval certificate expires. The message appears 92 days in advance when the card is removed. | Book an appointment with your workshop to replace the DTCO before the deadline. | Medium |
Faults — hardware malfunctions (workshop within 7 days)
| Message | Cause (from manual) | What to do | Severity |
|---|---|---|---|
| x internal fault xx | Serious malfunction in the DTCO 4.1x. Possible causes: unexpected program/process timing error, blocked buttons, communication malfunction with external devices or instrument display, malfunction at the pulse output. | Acknowledge. Check buttons. Have connecting cables / connected recording equipment inspected by an authorised workshop. | Critical |
| x1 internal fault xx | Malfunction in the card mechanics (slot 1), e.g. the card lock is not closing. | Remove the tachograph card and reinsert it. If it persists, consult a workshop. | High |
| x time fault xx | UTC time of the DTCO is not plausible or the real-time clock is faulty. Newly inserted driver/company cards are rejected to avoid inconsistent data. | Acknowledge. The DTCO must be replaced or reset by an authorised workshop as soon as possible. | Critical |
| x printer malfunction | The printer's supply voltage has failed or the temperature sensor for the printing head is defective. | Confirm. Repeat the print, possibly after cycling the ignition. If unresolved, workshop visit. | Medium |
| x download fault xx | Malfunction while downloading data to an external device (download key or remote download box). | Confirm. Repeat the download. Get connection cables (loose contact?) or the external device checked. | Medium |
| x sensor fault xx | The motion sensor indicates an internal malfunction after its self-test. | Acknowledge. Workshop inspection — sensor replacement may be required. | Critical |
| x1 card fault xx | During reading or writing of the tachograph card a communication malfunction has occurred — typically caused by dirty contacts. Some driver data may not have been written. | Confirm. Clean the card contacts (dry cloth) and reinsert. If recurring, replace the card. | Medium |
| x internal GNSS fault xx | Error on the GNSS device: internal failure, short circuit of the external GNSS antenna (option), or no connection to the external antenna. | Acknowledge. Consult an authorised workshop. | High |
| x internal DSRC fault xx | Internal error on the DSRC module (remote roadside-check radio), or the antenna is faulty / not connected. | Confirm. Workshop must check the DSRC module, cables, and external antenna. | Medium |
| x internal sensor fault xx | The self-test of the internal acceleration sensor has failed more than 10 times and the reset attempt was faulty. | Confirm. Consult an authorised specialist workshop without delay. | Critical |
| x ITS fault xx | An error on the internal Bluetooth component (ITS data interface). | Confirm. Consult an authorised specialist workshop. | Low |
Driving-time warnings (compliance pre-warnings, not faults)
| Message | Meaning | Action |
|---|---|---|
| 1 break! 04h15 00h15 | Take a break — continuous driving has reached 4 hours 15 minutes (pre-warning). | Confirm. Plan a 45-minute break in the next 15 minutes. |
| 1 break! 04h30 00h15 | Driving time exceeded — the 4 hours 30 minutes continuous-driving limit has been reached. | Stop and take a break (45 min, or 15 + 30 split). |
| 1 driving time 24h / | / || | End of daily (24h), weekly (|) or fortnightly (||) driving time is approaching. Pre-warning time is configurable. | Confirm. End driving and take the required rest under Reg 561/2006. |
| 1 rest in 01h45 | The next daily or weekly rest is due soon (configurable pre-warning). | Plan your next rest stop in good time. |
| 1 working time 24h 09h30 | End of daily (24h) or weekly (|) working time under the WTD is approaching. | Confirm. End the working day and take the required rest. |
| 1 working time 04h15 | End of the maximum uninterrupted working time (6 hours under WTD) is approaching. | Plan a break in the next 15 minutes. |
Operational notes (informational, auto-dismiss after 3 s)
| Note | Meaning & resolution |
|---|---|
| ? please enter | The unit is waiting for an entry during a manual-entry sequence. Press OK and continue. |
| o no paper xx | The printer has no paper or the printer drawer is not seated correctly. Insert a new roll; restart any interrupted print via the menu. |
| printout not possible xx | Print is impossible because the ignition is off (ADR variant), the print head is overheated, the printer is busy, or supply voltage is wrong. Wait for the cause to clear. |
| printout delayed | Print interrupted because the thermal head is too hot. Wait — the print continues automatically once cool. |
| ejection not possible xx | Card eject was refused: data being read or transferred, day change underway, vehicle moving, or (ADR) ignition off. |
| ?1 recording inconsistent xx | Inconsistent ordering of dates in the driver-card records. Will clear once new data overwrites the faulty entries. |
| 1 please eject the card xx | Error when writing data to the driver card. The card is ejected and re-read; if it fails again, a printout of the last activities is started. |
| 1 card error xx | An error occurred while processing the inserted tachograph card. The card is rejected and ejected. Clean the contacts and reinsert. |
| 1 wrong card type xx | The inserted card is not a tachograph card. Insert a valid tachograph card. |
| 1 please clean card! | The DTCO had problems reading or writing the card. Clean both card and card drawers. |
VDO numeric fault-memory codes (001–066)
These numeric codes are read from the unit's fault memory with a VDO workshop diagnostic tool (SDS / CTCII) — they are not shown to the driver during normal use. The numbering is consistent across DTCO generations (1381 and 4.1) and each number maps to one of the Annex I C events / faults described in the message tables above. Type a number such as 005 into the search box at the top of this section.
| Code | Meaning | Severity |
|---|---|---|
| 001–2, 004–5 | Internal device error | Critical |
| 006 | Time error | Critical |
| 007 | Display fault | High |
| 009 | Calibration error | High |
| 010 | Speed-signal output (B7) fault | Medium |
| 012 | Download error | Medium |
| 013–14 | CAN bus fault | Medium |
| 015 | Display communication loss | Medium |
| 016 | Sensor fault (self-test) | Critical |
| 017–18 | Sensor data integrity error | Critical |
| 019 | Sensor power interruption | Medium |
| 020–22 | Sensor communication error | High |
| 023 | Sensor authentication / pairing error | High |
| 024 | Unknown sensor serial number | High |
| 025 | Data memory error | Critical |
| 026 | Housing opened (security breach) | Critical |
| 028 | Driving without card | Critical |
| 029 | Cards conflict | Medium |
| 030 | Overspeed | High |
| 031 | Power interruption | Medium |
| 034 | Card ejection not possible | Medium |
| 036 | Printing / display not possible | Medium |
| 037 | Printing delayed | Info |
| 038 | Printer drawer open | Medium |
| 039 | Out of paper | Medium |
| 040 | Card mechanism fault, slot 1 | High |
| 041 | Card communication error, slot 1 | High |
| 042 | Card data authenticity, slot 1 | High |
| 043 | Card missing, slot 1 | High |
| 044 | Card not closed, slot 1 | Low |
| 045 | Time overlap, slot 1 | Medium |
| 046 | Insertion while driving, slot 1 | Low |
| 047 | Card authentication, slot 1 | High |
| 048 | Card not valid, slot 1 | High |
| 049 | Record inconsistency, slot 1 | Medium |
| 050 | Card cannot be read, slot 1 | High |
| 051 | Wrong card type, slot 1 | Medium |
| 052 | Card blocked, slot 1 | High |
| 053–66 | Card faults, slot 2 (co-driver) | High |
DTCO 4.0 / 4.1 — what a number on the display means (smart tachograph)
Newer VDO DTCO 4.0 and 4.1 units show a two-digit number next to the pictogram. Low numbers (001–066) are in the table above; the high numbers 80–98 belong to smart-tachograph functions (GNSS, DSRC, ITS). You can type any of them straight into the search box above.
| Display number | Meaning | Severity |
|---|---|---|
| 34 | Card ejection not possible | Medium |
| 80 | Vehicle motion conflict | Critical |
| 82 | Internal GNSS fault | Medium |
| 83 | Missing GNSS signal | Medium |
| 84 | Internal DSRC fault | Low |
| 85 | Communication error DSRC | Low |
| 86 | Time conflict | Medium |
| 87 | Sensor fault | High |
| 96 | GNSS anomaly (GNSS irregularities · anti-spoofing OSNMA) | High |
| 97 | Internal sensor fault | High |
| 98 | ITS / Bluetooth fault | Low |
| 67, 99 | Inconsistent record | Medium |
| 68–72 | Card / internal fault, slot 2 (co-driver) | Varies |
| 88–95 | Driving-time / rest operational note — not a fault | Info |
Stoneridge SE5000 Exakt Duo² (Rev 7.6)
Stoneridge SE5000 is the most common smart tachograph fitted to UK-registered HGVs and to fleets across the Nordics. The messages below are reproduced verbatim from the official Stoneridge SE5000 Exakt Duo² Driver & Company Manual, Rev 7.6 (Stoneridge Electronics AB, Örebro). Stoneridge's manual organises messages into four families, exactly mirroring the Annex I C classification: Messages (informational), Pre-warnings, Warnings and Faults.
Manual quote: "Faults are more critical than warnings and are displayed if there is a fault detected in the tachograph, in the sensor or driver card. In addition faults are presented if tampering with the equipment is detected. Faults are stored and can be printed."
Card-related messages
| Display | Type | Description (verbatim from manual) | Recommended action |
|---|---|---|---|
| Card 1 fault | Fault | The card in tray 1 is defective. Similar message for tray 2. Related to the card. | Eject and inspect visually. Clean with a damp cloth. If still faulty: workshop visit. |
| Card 1 auth.failure | Fault | The tachograph security check for the card in tray 1 failed. Related to the tachograph. | Eject and clean. If persists: workshop must inspect. |
| Card 1 time overlap | Warning | The last withdrawal time of the inserted driver card is later than the date/time of the tachograph. Related to the tachograph. | Check date/time on tachograph. Wait for overlap to elapse. |
| Card integrity error | Fault | Corrupt data detected when reading data from the card. Related to the card. | Clean and retry. If persists: replace card and visit workshop. |
| Card conflict | Warning | An invalid card combination has been detected. Related to the card. | Withdraw the offending card. |
| Card ins. while driving | Warning | A driver card was inserted while the vehicle was in motion. Related to the operator. | Continue the journey if the driver card is valid; event is recorded. |
| Card eject without saving | Message | Data could not be stored on the card withdrawn from tray 1 due to an error. | Eject, clean, retry. Self-test if persists. |
| Card expired | Message | The card in tray 1 has expired. Related to the operator. | Remove the card and replace with a valid one. |
| Card expires in xx days | Message | The card inserted in tray 1 expires in xx days (0–30). Related to the operator. | Contact the responsible authority to get a new card. |
| Insertion of a non valid card | Warning | A non-valid card has been inserted into a slot. Related to the operator. | Eject the non-valid card. |
| Last sess. not closed ok | Warning | The driver card in tray 1 was ejected incorrectly during the last session. The previous card withdrawal in tray 1 was not completed correctly by the tachograph. | Eject and clean. Self-test if persists. |
| Wrong PIN! Card locked | Message | Wrong PIN entered too many times (workshop card). Related to the card. | Eject and replace with a valid card. |
Sensor & vehicle motion faults
| Display | Type | Description (verbatim) | Action |
|---|---|---|---|
| Sensor auth.failure | Fault | The tachograph does not detect the sensor / does not recognise the connected sensor as the one installed. Related to the motion sensor. | Visit a digital tachograph workshop. |
| Sensor cable fault | Warning | Sensor data error / motion sensor data error. Related to the motion sensor. | Workshop must check wiring and sensor. |
| Sensor comms error | Fault | Motion sensor communication error. Related to the motion sensor. | Workshop replacement. |
| Sensor data error | Warning | Signal failure between motion sensor and tachograph. Related to the motion sensor. | Workshop must check. |
| Sensor data integrity error | Fault | Internal motion sensor error, stored data integrity failure. Related to the motion sensor. | Sensor replacement likely. |
| Sensor data transfer error | Fault | The motion sensor and tachograph do not communicate. Related to the motion sensor. | Workshop visit. |
| Sensor fault no acknowledge | Fault | Motion sensor communication error. | Workshop visit. |
| Sensor power high / low | Fault | Motion sensor power too high or too low. Related to the motion sensor. | Workshop must check supply. |
| Sensor no power signal | Fault | Motion sensor has no power. Related to the motion sensor. | Workshop must check supply. |
| Sensor unauth. case open | Fault | Unauthorized opening detected. Related to the motion sensor. | Workshop must inspect — possible tampering. |
| Secondary sensor fault | Fault | No or erroneous data from the second source motion sensor. Related to the motion sensor. | Workshop must check. |
| Unauth. change of sensor | Fault | The sensor has been changed since last pairing. Related to the motion sensor. | Workshop must re-pair. |
| Vehicle Motion Conflict | Fault | 2nd source of motion sensor and primary motion sensor data contradicts. Related to the motion sensor. | Workshop must check. |
| Hardware sabotage | Fault | Card has been removed by force or a tampering with the hardware has been detected. | Workshop visit — investigation required. |
Tachograph (VU) internal faults & power
| Display | Type | Description (verbatim) | Action |
|---|---|---|---|
| VU internal fault | Fault | The tachograph has detected an internal fault. Related to the tachograph. | Visit a workshop. |
| Data integrity error | Fault | The user data stored in the tachograph has errors. Related to the tachograph. | Workshop visit immediately. |
| Unauth. VU opening | Fault | The tachograph unit case has been opened. Related to the tachograph. | Workshop must investigate tampering. |
| Power supply interruption | Warning | The tachograph supply voltage is below or above the limit for correct operation or has been disconnected. The power supply has been interrupted for more than 200 milliseconds. Cranking voltage should not cause this event. | Workshop must check vehicle electrical supply if recurring. |
| Driving w/o valid card | Warning | Driving without an appropriate card, or with an inappropriate card combination. Related to the operator. | Stop and remove inappropriate card. Insert a valid driver card. |
| Over speeding | Warning | The vehicle speed has exceeded the speed limit set for 1 minute and will be stored. Related to the operator. | Observe the specified speed limit. |
| Overspeeding pre-warning | Message | The vehicle is exceeding the over speed limit set. After 1 minute of continuous over speeding the warning will be stored. | Slow down before the 1-minute threshold. |
| Download failed | Warning | A failure when trying to download data from the tachograph. Related to the tachograph/card. | Check connector and equipment, retry. If persists: workshop. |
| UTC adjust not allowed | Message | UTC time adjustment more than ±1 minute once a week is not allowed. | If UTC has deviated by more than 20 min, workshop must calibrate. |
Printer messages
| Display | Type | Description (verbatim) | Action |
|---|---|---|---|
| Printer high temperature | Message | The printing could not start, or the ongoing printing has been interrupted, because the temperature of the printer is too high. | Wait until the printer cools, then retry. |
| Printer low temperature | Message | The printing could not start because the temperature of the printer is too low. | Wait until printer warms; workshop if persists. |
| Printer low power | Message | The ongoing printing has been interrupted because the tachograph input voltage is too low. | Check ignition is on; check battery voltage and connections. |
| Printer out of paper | Message | The ongoing printing has been interrupted because the printer is out of paper. | Replace paper. |
Driving-time warnings (Stoneridge pre-warnings & warnings)
| Display | Type | Meaning (verbatim) |
|---|---|---|
| Quarter left reminder | Message | The driver has 15 minutes left until the legal maximum continuous driving time of 4½ hours will be exceeded. |
| Time for break | Warning | The legal maximum continuous driving time of 4½ hours has elapsed (per Reg 561/2006). Take a minimum 45-minute break, or 15+30 split. |
| reminder break | Pre-warning | A reminder for a break according to the 6 h WTD rule (Directive 2002/15/EC). |
| daily drive time | Warning | Pre-warning and warning for 9-hour daily drive time. |
| end of daily drive | Warning | Maximum daily driving time reached. |
| weekly drive time | Pre-warning | Maximum weekly driving time (56 h) approaching. |
| end of weekly drive | Warning | Maximum weekly driving time reached. |
| 2-week drive time | Pre-warning | Maximum 2-week driving time (90 h) approaching. |
| end of 2-week drive | Warning | Maximum 2-week driving time reached. |
| weekly work time | Pre-warning | Reaching the weekly working time according to the 60-hour WTD rule. |
| end of weekly work | Warning | The weekly working time is reached according to the 60-hour WTD rule. |
| reminder daily rest | Pre-warning | A reminder for the daily rest period. |
| reminder weekly rest | Pre-warning | A reminder for the weekly rest period. |
| time for daily rest | Warning | A warning for the start of daily rest. |
| time for weekly rest | Warning | A warning for the start of weekly rest. |
| Service pre-warning / Time for service | Message | Next calibration pre-warning / the tachograph is out of calibration. |
SE5000-8.1 Smart 2 — manufacturer-specific hex DTCs (ISO 16844-7)
The current SE5000-8.1 (Smart Tachograph 2) reports a 5-byte hexadecimal DTC per ISO 16844-7 in addition to the on-screen message. The codes below are reproduced from the Stoneridge SE5000-8.1 Control Manual, document 9000-103766P_0109 (Stoneridge Electronics AB).
| DTC | Message | Cause | What to do | Severity |
|---|---|---|---|---|
| 0001C0 | Printing stopped, out of paper | The printer has no paper. | Insert a new paper roll. | Low |
| 000900 | No ignition but speed pulses present | Ignition is off, yet the sensor detects speed pulses. | Check for vibration / interference; if recurring, workshop must check the sensor and pin B7. | High |
| 000D40 | Overspeeding pre-warning | Speed limit exceeded, but for less than 60 seconds. | Slow down. Driver-related — no workshop needed. | Medium |
| 000B78 | Calibration error | Two years have elapsed since the last calibration. | Recalibrate at an authorised workshop. | High |
| 000C31 | Internal GNSS fault | The internal GNSS receiver has stopped providing position data. | Power-cycle the tachograph and test-drive; if recurring, replace. | Medium |
| 002B80 | Time conflict (GNSS vs VU) | Internal and GNSS clocks differ by more than 1 minute after 12 hours. | Check the internal clock and GNSS time. Workshop. | Medium |
| 002C80 | Absence of GNSS position | No valid GNSS signal during 3 hours of cumulative driving. | Check GNSS reception and any obstructions around the antenna. | Medium |
| 002D80 | DSRC communication error | The vehicle unit cannot communicate correctly with the DSRC-VU module. | Check the DSRC-VU unit, cabling and CAN parameters. | Medium |
| 002E80 | GNSS Anomaly | GNSS detected an attack or message authentication failed (OSNMA). | Check for tampering. Restart and verify; replace if recurring. | Critical |
| 00FD0B | CAN bus off, TCO | The A-connector (TCO-CAN) is in "Bus Off" state. | Check the A-connector and cabling, CAN settings and termination (60 Ω). | High |
General events & security breach (SE5000-8.1)
| Message | Cause | What to do | Severity |
|---|---|---|---|
| Card conflict | An invalid card combination is detected (e.g. company + control card). | Withdraw the offending card. | Medium |
| Driving without appropriate card | Driving with no valid card, or with an invalid card combination. | Stop, insert a valid card and remove the inappropriate one. | Critical |
| Overspeeding | The speed limit was exceeded for at least 60 seconds. | Observe the permitted speed limit for the vehicle. | High |
| Power supply interruption (VU / MS) | Tachograph or sensor power was interrupted for more than 200 ms. | Check the vehicle power supply and wiring. | Medium |
| Motion data error (CNTR / No CNTR / Event) | The sensor reports speed without pulses, the counter disagrees, or a signature mismatch occurs. | Check the sensor, wiring and tampering; recalibrate if needed. | Critical |
| Motion sensor authentication failure | A motion-sensor authentication attempt failed. | Check the sensor and wiring; re-pair and recalibrate. | Critical |
| Unauthorised change of motion sensor | The sensor has been changed since the last pairing. | Inspect for tampering; repair and recalibrate. | Critical |
| Stored data integrity error | Data in the 365-day memory is corrupted. | Decommission and replace the tachograph. | Critical |
| Hardware sabotage | The card was removed by force. | Inspect the card reader. Decommission and replace. | Critical |
| Security violation | Hardware tampering has been detected. | Decommission and replace the tachograph. | Critical |
Source: Stoneridge Electronics AB, SE5000-8.1 Smart 2 Control Manual, document 9000-103766P_0109, pp. 32–37.
Source: All Stoneridge messages above are reproduced from the SE5000 Exakt Duo² (Rev 7.6) Driver & Company Manual published by Stoneridge Electronics AB. The complete table covers all messages a driver may see; messages specific to workshop (calibration) mode are not shown here. The SE5000-8.1 Smart Tachograph 2 unit uses the same Annex I C message family structure with minor wording updates.
Actia SmarTach (Gen1 & Gen2)
Actia's SmarTach is the most common digital tachograph on French-registered HGVs and a frequent fitment across Spain, Italy and Portugal. Messages below are reproduced from the Actia SmarTach Driver Manual (2021, ref. c1c). Actia uses on-screen pictogram + short text; the wording is consistent with Annex I C terminology.
| Message | Meaning | What to do | Severity |
|---|---|---|---|
| Driving without card | Vehicle moving with no valid card in slot 1 — Annex I C Event recorded. | Insert a valid driver card. Print and annotate the period. | High |
| Insertion while moving | Card was inserted after the journey had already started. | Acknowledge — Event recorded on card. | Medium |
| Card not closed correctly | Previous session was not properly terminated. | Acknowledge; note for fleet records. | Medium |
| Card invalid / expired | Driver card has expired, has not yet activated, or authentication failed. | Renew the card with your member state authority. | Medium |
| Speed limit exceeded | Set speed limit exceeded for more than 60 seconds. | Reduce speed; event visible on download. | High |
| Movement conflict | Discrepancy between motion sensor and GNSS / odometer signal. | Workshop — possible tampering or wiring damage. | Critical |
| Power loss | Supply voltage dropped or was disconnected. | Acknowledge. Check supply if it recurs. | Medium |
| Security breach | VU enclosure opened or data integrity violated. | Mandatory workshop visit. | Critical |
| Sensor failure | Motion sensor failed self-test. | Workshop replacement. | Critical |
| Printer error | Printer cannot complete a print job. | Check paper / let it cool / replace mechanism if it persists. | Medium |
| GNSS missing | No position data for 3 hours of cumulative driving. | Confirm. Check antenna; ensure no metal obstruction. | Medium |
| UTC time mismatch | Difference between internal clock and GNSS time exceeds 1 minute. | Workshop will resync. | Medium |
| Internal fault | Generic VU malfunction — memory, RTC, software watchdog. | Workshop within 7 days. | Critical |
| Cards conflict | Incompatible card combination in slots 1 + 2. | Remove the conflicting card. | Medium |
| Drive > 4 h 30 | Continuous driving has exceeded 4 h 30 min without a break (KITAS motion sensor). | Stop immediately and take the mandatory 45-minute break. | High |
Actia's user-facing messages are deliberately concise; detailed numeric DTCs are accessible only through a workshop's CITO / SmarTach Tester.
EFAS-4 / EFAS-4.10
The EFAS-4 (originally Intellic, now Schneider Electric) is fitted to many German-built tractor units (MAN, DAF some configurations) and to a significant share of Polish-registered HGVs. Messages below come from the EFAS-4 Driver Manual, Edition 06.2022. EFAS uses two-letter on-screen codes plus a pictogram.
| Code | Message | Meaning | Action | Severity |
|---|---|---|---|---|
| E01 | No card | Vehicle moved without a valid driver card. | Insert card; print & annotate. | High |
| E02 | Card insertion | Card inserted after motion started. | Acknowledge. | Medium |
| E03 | Last session | Previous card session not closed. | Acknowledge; note for fleet. | Medium |
| E04 | Overspeed | Speed limit exceeded > 1 min. | Reduce speed. | High |
| E05 | Power loss | Supply voltage too low or interrupted. | Check supply if recurring. | Medium |
| E06 | Motion data | Inconsistent motion sensor pulses. | Workshop. | Critical |
| E07 | Movement conflict | Sensor disagrees with GNSS / odometer. | Workshop — tampering check. | Critical |
| E08 | Card conflict | Invalid combination of cards. | Remove conflicting card. | Medium |
| E09 | Time overlap | Negative UTC offset from last VU. | Workshop must correct. | Medium |
| E10 | Security breach | Enclosure tamper or data integrity error. | Mandatory workshop. | Critical |
| F01 | Internal fault | Generic VU hardware/software malfunction. | Workshop within 7 days. | Critical |
| F02 | Card mech | Card lock mechanism error. | Workshop. | High |
| F03 | Time fault | Real-time clock implausible. | Workshop — new cards will be rejected. | Critical |
| F04 | Printer | Printer mechanism failure. | Replace paper or workshop. | Medium |
| F05 | Downloading | Error during data download. | Retry; check cable. | Medium |
| F06 | Sensor fault | Motion sensor failed self-test. | Sensor replacement at workshop. | Critical |
| F07 | GNSS | Internal GNSS receiver or antenna fault. | Workshop check. | High |
| F08 | DSRC | Remote-check DSRC module fault. | Workshop will inspect antenna and CAN. | Medium |
EFAS-4.10 / 4.11 — hex DTCs (ISO 16844-7), top 12
EFAS units expose three code types: EFT (event/fault type per ISO), DTC (5-byte hex per ISO 16844-7) and a manufacturer-specific Service ID. The most important DTCs below are reproduced from the Bosch Intellic EFAS-4.10 Workshop Manual, Table 18 (DTCs and corresponding Service IDs).
| DTC | Meaning | What to do | Severity |
|---|---|---|---|
| 80 00 002007 | Motion sensor supply voltage above maximum | Check the sensor power supply and wiring. | High |
| 80 00 002003 | Motion sensor supply voltage below minimum | Check the sensor power supply and wiring. | High |
| 80 00 002180 | No real-time signal from the motion sensor (pin B3 interrupted) | Check pin B3 and the sensor power supply. | Critical |
| 80 00 002280 | Faulty real-time sensor signal (pin B3 or IMS error) | Check pin B3 and the sensor checksum. | Critical |
| 80 00 002452 | Distance-sensor data integrity error | Authorised workshop must check the sensor. | High |
| 80 00 002508 | Motion sensor fault | Authorised workshop — sensor replacement. | Critical |
| 40 00 000200 | Card fault, slot 1 | Clean the contacts and reinsert; if recurring, new card. | High |
| 40 00 000300 | Card fault, slot 2 | Clean the contacts and reinsert. | High |
| 80 00 000660 | Printer out of paper | Insert a new paper roll. | Low |
| 40 00 000900 | Motion sensor pulses with ignition off | Check for vibration, the sensor and wiring. | High |
| 40 00 000C31 | Internal memory fault | Authorised workshop; replace if it cannot be repaired. | Critical |
| 80 00 000D40 | Calibration data incorrect or incomplete | Recalibrate at an authorised workshop. | Critical |
EFAS-4 numeric codes (E01–E10, F01–F08) are the unit's internal mnemonics — the underlying Annex I C event/fault is the legally relevant identifier and is recorded the same way as on any other unit.
TAGRA decodes every one of these messages automatically.
When you download a driver card or vehicle unit into TAGRA, every event and fault is matched to its Annex I C definition with a plain-English explanation. Try the full software free for 30 days — no card required.
Try TAGRA free for 30 days →Top 10 most common tachograph messages in practice
Of the 200+ messages above, ten account for the vast majority of what real drivers see day to day — and almost all of them are operational rather than catastrophic. Knowing how to react to these ten will keep most shifts running smoothly and most enforcement officers satisfied.
| # | Message | Why it happens | First response |
|---|---|---|---|
| 1 | Card 1 communication error | Dirty contacts on the driver card or in the card drawer. Card inserted slightly off-axis. Common in winter when cards live in cold pockets and condensation forms on chip contacts. | Eject. Wipe chip with a dry cloth (no liquid). Reinsert. If still failing, try the spare slot. |
| 2 | No paper / printer drawer open | Paper roll ran out, or the printer drawer was opened during a print job. Wrong paper type (only thermal paper marked for digital tachographs is accepted). | Insert a new roll, drawer must click shut. Always carry a spare roll. |
| 3 | 1 break! 04h15 | Continuous-driving timer is approaching 4 h 30 min. Pre-warning is configurable (commonly 15 minutes before). | Plan a 45-minute break in the next 15 minutes (or split into 15 + 30). |
| 4 | Card insertion while driving | Driver forgot to insert the card before driving off, then realised and inserted it on the move. | Stop briefly. Re-insert correctly. Event is recorded on the card but is not a fault. |
| 5 | Last session not closed | Driver pulled card too quickly from the previous vehicle, or the previous VU shut down before writing the closing record. | Acknowledge. Mention to the fleet manager — the previous VU may need a workshop visit. |
| 6 | Power supply interruption | Battery jump-started, wiring fault, or vehicle stood overnight with a flat battery. | Acknowledge. If recurring, have the supply circuit inspected — repeated power loss is suspicious to enforcement. |
| 7 | GNSS missing / no position data | Cumulative 3 hours of driving with no usable GNSS fix — typical in tunnels, underground depots, or with a blocked antenna. | Confirm. Check the antenna routing and that nothing metallic has been placed on the dash above it. |
| 8 | Country entry required | Smart Tachograph 2 prompts you to confirm the country (and on Smart Tacho 2, the border crossing) every time you start a new shift. | Use the menu: begin country → select code. On Smart Tacho 2 the unit also requests confirmation when GNSS detects a border. |
| 9 | Calibration in days ?? | Two-yearly periodic inspection is approaching (warning typically 28 days in advance). | Book the workshop appointment immediately — driving with an out-of-calibration tachograph is a serious offence. |
| 10 | 1 download in days ?? | The next mandatory driver-card download is due (warning typically 14 days in advance). EU rules require download at least every 28 days. | Hand the card to the fleet or download yourself. If you miss the deadline, the data is still retained but the office may sanction you. |
Critical-error workflow: what to do when a fault appears roadside
A genuine x Fault message — sensor fault, motion conflict, internal fault, security breach, time fault — is different from an operational note: the tachograph can no longer record your activity reliably, and you are legally required to keep manual records and have the unit inspected by an authorised workshop within seven days (Article 37 of Regulation 165/2014). The following five-step workflow is the official procedure described in every manufacturer's manual.
- 1 Acknowledge the message and continue safely. Press the OK button to silence the flashing display. The fault is now recorded in the mass memory and on your card — confirming it does not erase the event. Stay calm and find a safe place to stop.
- 2 Print a driver-activities printout from the VU. Menu: print → driver 1 → activities → 24h day. The printout will include the fault entry and a timestamp. Take a fresh printout each subsequent day until the tachograph is repaired.
- 3 Start manual records on the reverse of the printout. For every period the tachograph can no longer record correctly, write by hand: start time, end time, activity (drive / other work / availability / rest), location, vehicle registration. This sheet is your legal evidence for any roadside inspection until the unit is fixed.
- 4 Inform your fleet manager immediately. Phone, message or email — whatever your operation uses. The fleet has to log the fault, plan the workshop appointment, and confirm that the trip can continue under manual recording. Driving past 7 days with a known unrepaired fault exposes the operator to substantial fines.
- 5 Book the authorised workshop appointment within 7 days. Only an authorised tachograph workshop (holding a workshop card and the appropriate diagnostic tools) may repair, recalibrate or replace the VU. After repair, the workshop will perform a calibration and provide a fitting plate / calibration record that must be kept with the vehicle.
One critical exception: if the fault is security breach or sensor fault with motion conflict, the unit may automatically eject the card and refuse to record further activities at all. In that case, the entire shift must be hand-written, and the workshop visit becomes urgent rather than the standard 7-day rule. Continuing to drive without manual records in this scenario is a serious offence in every EU and EEA member state.
Official sources & manufacturer manuals
Every message, threshold and procedure above is reproduced from one of the following publicly available, official documents. Where the manufacturer's English wording differs from common driver vocabulary, we have kept the manufacturer's exact text and added a plain-English explanation alongside.
- EU regulation — drivers' hours and AETR Regulation (EC) No 561/2006 — driving times, breaks and rest periods. Directive 2002/15/EC — Working Time Directive for mobile road workers. AETR — European Agreement on the Work of Crews engaged in International Road Transport. EUR-Lex: Regulation 561/2006 (EN)
- EU regulation — tachograph technical specification Regulation (EU) No 165/2014 — legal basis. Commission Implementing Regulation (EU) 2016/799, Annex I C — full technical specification of the smart tachograph (Events, Faults, data structures). EUR-Lex: 2016/799 / Annex I C (EN) · EUR-Lex: 165/2014 (EN)
- VDO DTCO 4.1 — Continental Automotive Technologies Driver instruction manual, Edition 3 / 2024-08, BA00.1381.41 100 102. Covers DTCO 4.1, 4.1a and 4.1b. PDF download (English) — fleet.vdo.com
- VDO DTCO 4.0 — Continental Automotive Technologies Earlier Smart Tacho 1 unit, still in widespread service. Driver manual, Edition 2 / 2022. PDF download (English) — fleet.vdo.com
- Stoneridge SE5000 Exakt Duo² — Stoneridge Electronics Driver & Company Manual, Rev 8.x. Reference unit for the UK and Nordic markets. Manuals — stoneridgeelectronics.com
- Actia SmarTach — Actia Group SmarTach Gen1 and Gen2 driver guides; widespread on French and southern-European fleets. Product page — actia.com
- European Commission — DG MOVE Authoritative background on the smart tachograph rollout, amendments, and enforcement guidance. transport.ec.europa.eu — Smart tachograph
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