VOLVO
TRM-B10D668 - Trailer / Caravan Cable Error. Algorithm Based Failures. Event information
System
Trailer Module (TRM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
This is an event information code for a cable fault to the trailer or caravan. The tow hitch control module (TRM) has detected an external power source at a higher voltage than the car's system voltage connected to the trailer socket. The affected output is blocked, and the message indicates that the trailer needs service.
Possible causes
- A trailer or caravan with its own power source at a higher voltage than the car has been used
- Electrical fault in the connected trailer
What you can do
- 1Check that the caravan is not feeding the trailer socket from its own battery or power source
- 2If the caravan has its own battery, disconnect it before the caravan is connected to the car, as otherwise the message may return and the control module can be damaged
- 3Check the lighting circuits on the caravan or trailer so that none of them is fed from outside, except the rear fog lamp
- 4If the owner wants to charge the caravan battery while driving, a workshop can help, as this needs a different trailer socket
Symptoms you may notice2
- Text message in the display
- Trailer lighting does not work
What the fault can affect1
- The affected output on the trailer socket is blocked by the tow hitch control module
General guidance for car owners. Diagnosis on the car can point to a different cause.