VOLVO
ECM-2129 - Accelerator pedal (AP) position sensor, circuit 2.Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (13)
- Volvo C30 (2007–2013)2007–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo C30 (2007–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo C30 (2007–2013)2011–2013Engine B4204S3, B4204S4 only
- Volvo S40 (2004–2013)2005Engine B4184S11 only
- Volvo S40 (2004–2013)2006Engine B4184S11, B4184S8 only
- Volvo S40 (2004–2013)2007–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo S40 (2004–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo S40 (2004–2013)2011–2012Engine B4204S3, B4204S4 only
- Volvo V50 (2004–2013)2005Engine B4184S11 only
- Volvo V50 (2004–2013)2006Engine B4184S11, B4184S8 only
- Volvo V50 (2004–2013)2007–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo V50 (2004–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo V50 (2004–2013)2011–2012Engine B4204S3, B4204S4 only
What does this fault code mean?
The code is stored when the engine control module detects an incorrect signal on circuit 2, or when circuits 1 and 2 do not match. It is tested while driving, and the fault may be caused by a damaged accelerator pedal position sensor.
Possible causes
- Damaged accelerator pedal position sensor
What you can do
- 1Start by checking the connectors at the accelerator pedal for play and corrosion, and the wiring for chafing
- 2Have a diagnostic tool? Follow the pedal movement in live data while you slowly press and release the pedal, and check that circuit 1 and circuit 2 follow each other
- 3Use a multimeter to check that the circuit 2 signal wire is not broken or short-circuited to ground or voltage
- 4If the wiring is sound but the fault remains, have a workshop check the accelerator pedal position sensor
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.