What it means: the driver card in card slot 1 can't be read or written to. The unit gets no usable response from the chip on your card.
Can you keep driving: yes, but log manually while it persists.
What fault 50 means
Every driver card carries a chip, similar to a bank card. Fault 50 means the unit can't address that chip at all, no data out, and nothing written back in either.
Usually the cause is the card itself: worn or damaged contact points, a cracked chip, or a card that's been inserted at the wrong angle too many times. Sometimes it's the reader in the unit itself, dirty or damaged pins. You only know for sure with a different card or a different tachograph.
The difference with 41
41 and 50 look similar but aren't the same. 41 is a communication fault: the unit and the card do talk to each other, just not cleanly, usually fixed by cleaning the contacts and reinserting the card. 50 is heavier: there's no usable communication at all. If cleaning and reinserting doesn't change anything, that points to 50 rather than 41, and the card itself is suspect number one.
Can you keep driving
Yes, with the same two obligations as any malfunction: the company has it repaired as soon as possible, and you log manually.
What to log right away
While the tachograph is unserviceable or malfunctioning, the driver shall mark data enabling him to be identified (name, driver card or driving licence number), including a signature, as well as the information for the various periods of time which are no longer recorded or printed out correctly by the tachograph: (a) on the record sheet or sheets, or (b) on a temporary sheet to be attached to the record sheet or to be kept together with the driver card.
Regulation (EU) No 165/2014, Article 37(2).
Start the manual record straight away: your name, driver card or licence number, a signature, and your driving and rest times from the moment the fault appeared. If it turns out the card itself is defective, you also need to request a replacement card, usually within seven calendar days of reporting it as damaged.
Who has to fix it, and by when
In the event of the breakdown or faulty operation of a tachograph, the transport undertaking shall have it repaired by an approved fitter or workshop, as soon as circumstances permit. If the vehicle is unable to return to the transport undertaking's premises within a period of one week calculated from the day of the breakdown or of the discovery of defective operation, the repair shall be carried out en route.
Regulation (EU) No 165/2014, Article 37(1). Accessed 25 September 2026.
If the unit's reader is at fault, the repair obligation sits with the company. If it's your card that's defective, replacing it is on you, through the card-issuing authority.
What it costs
A replacement driver card has its own issuing fee, which the tachograph regulation doesn't set, it depends on the issuing country. A genuine reader fault is a workshop cost. Keep your manual record until whichever it is has been resolved and logged.
Also read
Sources
- Regulation (EU) No 165/2014 on tachographs in road transport, Article 37, consolidated version. EUR-Lex
- VDO DTCO 4.0, manufacturer's official Message summaries: code 050 — "Card defective (drawer 1)".
Legal text quoted verbatim from the consolidated English version published on EUR-Lex, accessed 25 September 2026. VDO does not publish an official fault-code glossary in English; the plain-language description above is our own translation of the manufacturer's documentation, the legal citation is not.
Stuck? See where there is still room.
Drivers report what they see themselves. Parking full, traffic, hazard, roadworks. Open the app and stop driving alone.