VOLVO
ECM-950F - Accelerator pedal (AP) position sensor. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
7 modelsC70 Cabriolet (1998–2005), C70 Coupé (1998–2002), S60 (2001–2009), S70 (1997–2000), S80 (1999–2006), V70 (1997–2000), V70 (2000–2008)
Show models by year and engine (20)
- Volvo C70 Cabriolet (1998–2005)2000Engine B5244S only
- Volvo C70 Coupé (1998–2002)1999Engine B5254S DENSO only
- Volvo C70 Coupé (1998–2002)2000Engine B5244S only
- Volvo S60 (2001–2009)2001Engine B5244S, B5244S2 only
- Volvo S60 (2001–2009)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S60 (2001–2009)2003–2005Engine B5244SG, B5244SG2 only
- Volvo S60 (2001–2009)2006–2008Engine B5244SG only
- Volvo S70 (1997–2000)1999Engine B5254S DENSO only
- Volvo S70 (1997–2000)2000Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)1999–2000Engine B5244S, B5244S2 only
- Volvo S80 (1999–2006)2001Engine B5244S, B5244S2, B5244SG only
- Volvo S80 (1999–2006)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2003–2005Engine B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2006Engine B5244SG only
- Volvo V70 (1997–2000)1999Engine B5254S DENSO only
- Volvo V70 (1997–2000)2000Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2001Engine B5244S, B5244S2, B5244SG only
- Volvo V70 (2000–2008)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2003–2005Engine B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2006–2008Engine B5244SG only
What does this fault code mean?
The engine control module (ECM) compares the two signals from the accelerator pedal position sensor, one analogue and one pulse-width modulated (PWM). If they differ by more than allowed for a longer time, the code is stored. A larger difference is allowed while the pedal is moving, for example during acceleration.
Possible causes
- Connector on the analogue signal wire has worked loose or has high contact resistance
- Open circuit in the power supply to the accelerator pedal sensor
- Open circuit in the ground lead to the accelerator pedal sensor
- Fault on the PWM wire running from the engine control module (ECM) to the electronic throttle module (ETM)
- Defective system relay
- Defective accelerator pedal position sensor
What you can do
- 1Read out any other fault codes in the engine control module. If ECM-9180, ECM-918F, ECM-9520, ECM-9530 or ECM-9540 are stored, troubleshoot those first
- 2Check the connectors and wiring between the accelerator pedal sensor and the engine control module for loose connections, contact resistance and corrosion
- 3With a multimeter, check the pedal sensor's supply voltage and ground connections, and that no voltage difference exists between the ECM and the sensor
- 4If you have a diagnostic tool: press the pedal down slowly and follow both pedal signals in live data. They should track each other steadily without jumps
- 5After repair: clear the code, cycle the ignition off, on and off again, then test drive. A workshop can load upgraded software if one exists for the car
Symptoms you may notice1
- Poor accelerator pedal response, and the engine reacts more sluggishly than normal when accelerating
What the fault can affect3
- The throttle opens more slowly, since it is then controlled by only one of the PWM signals
- The throttle closes when braking
- The accelerator pedal position is ignored while the brake pedal is pressed
General guidance for car owners. Diagnosis on the car can point to a different cause.