Common Digital Tachograph Errors and Problems
Master Technical Guide 2026: Diagnosing error codes, card reading failures, and solutions for Smart Tachographs V1 and V2.
Chapter 1: Hardware Complexity in the Smart Era
With the mandatory introduction of the second-generation smart tachograph (V2), errors have evolved from simple mechanical failures into complex software and geolocation conflicts. In 2026, an error on your device screen is not just an inconvenience; it is a potential very serious infringement if not managed within legal timeframes.
Many problems experienced by drivers today are related to GNSS communication or card authentication. Understanding what an error code means can save you unnecessary workshop visits or, even worse, fines for driving with supposedly faulty equipment that only required a reset procedure or contact cleaning.
Chapter 2: Most Frequent Error Codes and Solutions
Error 20 / Card Failure
This is the most common error. It can indicate that the card chip is dirty or damaged. Before requesting a new card:
- Clean the chip with a dry, lint-free cloth.
- Try the card in Slot 2.
- Verify the expiration date.
Motion Conflict Error (Code 17)
Occurs when the speed sensor (KITAS) and the GNSS signal do not match. This is often a symptom of interference or, in the worst case, will be interpreted as a suspicion of tampering during a roadside inspection.
Chapter 3: Download Problems and File Corruption
The obligation to download data every 28 days (driver) and 90 days (vehicle) generates recurring technical issues with .DDD files.
3.1. Invalid Digital Signature
Sometimes the file downloads but appears as "Invalid Signature" when uploaded to the control platform. This usually happens due to a power supply interruption during download or using download keys with outdated firmware that do not support the new V2 tachographs.
3.2. Data Gaps in the Record
If the tachograph fails to record a period, it is often due to misuse of the activity selector or incorrectly performed manual entries at the start of the shift. These errors are "invisible" on the tachograph screen but fatal in an audit.
Chapter 4: Fault Reference Table
| SYMPTOM | PROBABLE CAUSE | RECOMMENDED ACTION |
|---|---|---|
| Blank Screen / Won't Turn On | Blown fuse or critical battery level | Check the truck's fuse box |
| Card Won't Eject | Mechanical motor blockage | Use emergency ejection procedure |
| "Last session not closed" | Previous incorrect card withdrawal | Accept manual entry and check for gaps |
| Authentication Failure (V2) | Obsolete card certificate | Renew card at the transport office |
Chapter 5: Support FAQs
Preventive Maintenance as a Solution
Most "common" digital tachograph problems in 2026 are avoidable. Periodic cleaning of cards, using high-quality readers, and weekly data auditing allow for fault detection before the device locks up completely. At TachoTools, our software acts as a diagnostic scanner for your .DDD files, identifying recording errors before they reach an inspector's hands.
Support & Tools
Does your file show an error when uploading? Our system repairs it automatically.
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