What does fault code TCM-0518 mean?

Diagnostic fault code details for TCM-0518 (Volvo C30 (2007–2013), Volvo C30 (2007–2013), Volvo C30 (2007–2013)). Repair service at OBD Tuning.

VOLVO

TCM-0518 - Sensor group 2. Supply voltage too low

System

Transmission Control Module (TCM)

Volvo models this fault code applies to

Applies to the following models:

4 models

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

Show models by year and engine (10)

What does this fault code mean?

The supply voltage to sensor group 2 in the transmission is too low. Sensor group 2 monitors the shift forks for the even gears. The fault can be caused by a supply cable shorted to ground, damaged cables or connectors, or a damaged transmission control module.

Possible causes

Power supply cable shorted to ground
Damaged cables or connectors
Damaged transmission control module (TCM)

What you can do

1Read the fault codes and clear TCM-0518. Drive the car to see whether the code returns
2Use a multimeter to check that the supply cable to sensor group 2 has no contact with ground (the body)
3Go over the connectors and wiring at the transmission for corrosion, loose connections and chafed cables
4Have a workshop read the voltage to the sensors with diagnostic equipment. Replace the control module if the fault is inside it

Symptoms you may notice5

Malfunction Indicator Light (check engine) lit or behaving abnormally
Yellow warning symbol and text message in the display
No automatic gear changes
Shifts hard or jerky
Shifts too early, too late or too often

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