VOLVO
ECM-0504 - Stop lamp switch. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (12)
- Volvo C30 (2007–2013)2007–2010Engine B4164S3, D4204T only
- Volvo C30 (2007–2013)2011–2012Engine B4164S3 only
- Volvo C70 (2006–2013)2008Engine D4204T only
- Volvo C70 (2006–2013)2009–2010Engine D4204T only · Transmission MMT6, MPS6 only
- Volvo S40 (2004–2013)2004Engine D4204T, D4204T2 only
- Volvo S40 (2004–2013)2005–2006Engine B4164S3, D4204T, D4204T2 only
- Volvo S40 (2004–2013)2007–2010Engine B4164S3, D4204T only
- Volvo S40 (2004–2013)2011–2012Engine B4164S3 only
- Volvo V50 (2004–2013)2004Engine D4204T, D4204T2 only
- Volvo V50 (2004–2013)2005–2006Engine B4164S3, D4204T, D4204T2 only
- Volvo V50 (2004–2013)2007–2010Engine B4164S3, D4204T only
- Volvo V50 (2004–2013)2011–2012Engine B4164S3 only
What does this fault code mean?
The control module verifies the brake pedal sensor and stop lamp switch signals. A fault in either circuit, or in CAN traffic between the BCM and the engine module, sets the code. It shows up with the ignition on and the pedal depressed.
Possible causes
- Incorrectly installed stop lamp switch
- Contact resistance or oxidation at the stop lamp switch connections
- Open circuit in the feed to the stop lamp switch
- Open circuit or short to ground or voltage in the signal wire to the stop lamp switch
- Damaged stop lamp switch
- Fault in the brake control module (BCM), which a workshop needs to trace
What you can do
- 1Fault codes in the BCM and CEM modules come first, since they may be the cause
- 2Check that the fuses are intact. Their locations are shown in the instruction manual or on the fuse box cover
- 3Make sure the stop lamp switch sits properly and that its bracket is intact. Do not adjust its position yourself, as it needs correct setting
- 4Switch off the ignition and check the stop lamp switch connector for contact resistance and oxidation
- 5The brake lights must work. If they do not work when you press the brake, fix the fault before driving, and have a workshop check the signal wire
Symptoms you may notice3
- Poor performance and lack of power
- Yellow warning symbol and text message in the display
- Cruise control does not engage
What the fault can affect1
- Cruise control is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.