VOLVO
TRM-9102 - Trailer stop lamp. Algorithm Based Failures
System
Trailer Module (TRM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsC30 (2007–2013), C70 (2006–2013)
Show models by year and engine (2)
What does this fault code mean?
The tow hitch control module (TRM) has found that the brake light input signals for the trailer do not agree. One signal comes over a direct wire from the central electronic module (CEM), and the other over the CAN network. Normally nothing is noticed, but in extreme cases the trailer lighting can stop working.
Possible causes
- Open circuit in the direct wire for the brake light signal
- Wire short-circuited to ground
- Contact resistance or oxidation in the connections
- Short circuit in the connections
- Open circuit in the CAN wire
What you can do
- 1Check the connectors to the tow hitch control module and to the left rear light for looseness, oxidation and contact resistance
- 2Use a multimeter to check that the brake light signal wire has no open circuit or contact with ground
- 3Remove any trailer connector from the socket before troubleshooting
- 4Have a workshop check the CAN wire and the central electronic module (CEM) if the fault remains
Symptoms you may notice2
- Normally no symptoms are noticed
- In extreme cases the trailer lighting does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.