What does fault code TRM-1A03 mean?

Diagnostic fault code details for TRM-1A03 (Volvo C30 (2007–2013), Volvo C30 Electric (2011–2013), Volvo C70 (2006–2013)). Repair service at OBD Tuning.

VOLVO

TRM-1A03 - Control module. Internal fault

System

Trailer Module (TRM)

Volvo models this fault code applies to

Applies to the following models:

5 models

C30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)

Show models by year and engine (5)

What does this fault code mean?

The tow hitch control module (TRM) has detected an internal fault. The cause may be incorrect programming or a fault in the module itself, and it can make the trailer lights malfunction and light the information lamp and show a message in the display.

Possible causes

Incorrect programming of the tow hitch control module (TRM)
Fault in the tow hitch control module (TRM)

What you can do

1Remove any trailer connector from the socket before troubleshooting
2Disconnect the battery negative terminal for a while and reconnect it, then read the fault code
3Have a workshop download new software into the tow hitch control module and reprogram it
4If the fault remains after reprogramming, the tow hitch control module needs replacing

Symptoms you may notice3

Trailer lights do not work correctly
Information lamp lit
Message in the text display

General guidance for car owners. Diagnosis on the car can point to a different cause.