VOLVO
TRM-8F04 - Right turn signal lamp. Signal too high
System
Trailer Module (TRM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (3)
What does this fault code mean?
The trailer module (TRM) checks the wiring to the trailer socket when no trailer is connected. It has detected too high a signal on the line to the right-hand direction indicator, pointing to a short circuit to supply voltage somewhere between the module and the socket.
Possible causes
- Short circuit to supply voltage on the right-hand indicator line to the trailer socket
- Moisture, corrosion or damage in the trailer socket or its connectors
What you can do
- 1Check the trailer socket for moisture, corrosion and damage – it is exposed to road salt
- 2Inspect the wiring from the socket along the towbar for pinching
- 3Check whether an adapter or a retrofitted accessory is connected to the towbar wiring
- 4If the fault remains, have the wiring and the trailer module checked by a workshop
Symptoms you may notice2
- The trailer lights do not work correctly
- Information lamp and message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.