VOLVO
ECM-P050423 - Brake Switch A / B Correlation. General Signal Failures. Signal stuck low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V70 (2008–), XC60 (2009–)
Show models by year and engine (20)
- Volvo S60 (2011–)2011Engine B4164T, B4164T3, B4204T6, B4204T7 only
- Volvo S60 (2011–)2012–2014Engine B4164T, B4164T2, B4164T3, B4204T7 only
- Volvo S60 (2011–)2015Engine B4164T, B4164T2, B4164T3 only
- Volvo S80 (2007–)2010Engine B4204T6 only
- Volvo S80 (2007–)2011Engine B4164T, B4204T6, B4204T7 only
- Volvo S80 (2007–)2012–2014Engine B4164T, B4164T2, B4204T6, B4204T7 only
- Volvo S80 (2007–)2015Engine B4164T only
- Volvo V40 (2013–)2013Engine B4164T, B4164T3 only
- Volvo V40 (2013–)2014–2015Engine B4164T, B4164T3, B4164T4 only
- Volvo V40 Cross Country (2013–)2013–2015Engine B4164T only
- Volvo V60 (2011–)2011Engine B4164T, B4164T3, B4204T6, B4204T7 only
- Volvo V60 (2011–)2012–2014Engine B4164T, B4164T2, B4164T3, B4204T7 only
- Volvo V60 (2011–)2015Engine B4164T, B4164T2, B4164T3 only
- Volvo V70 (2008–)2010Engine B4204T6 only
- Volvo V70 (2008–)2011Engine B4164T, B4204T6, B4204T7 only
- Volvo V70 (2008–)2012–2014Engine B4164T, B4164T2, B4204T7 only
- Volvo V70 (2008–)2015Engine B4164T, B4164T2 only
- Volvo XC60 (2009–)2010Engine B4204T6 only
- Volvo XC60 (2009–)2011–2012Engine B4204T6, B4204T7 only
- Volvo XC60 (2009–)2013–2015Engine B4204T7 only
What does this fault code mean?
The engine control module (ECM) receives the brake pedal position from two switches. The code is set when the signal from them has stayed constantly low and no correct braking has been registered for a long time. The counter resets every drive cycle and at each correct braking. A fault in the central electronic module (CEM) may be the cause, so it is checked first.
Possible causes
- Diagnose the cause in the central electronic module (CEM)
- Break or short to ground or supply voltage on the brake light switch wire
- Break or short to ground or supply voltage on the brake pedal position sensor wire
- Contact resistance, oxidation or intermittent contact in the connector
- Break or short to ground or supply voltage on the brake pedal switch wire
What you can do
- 1Look for stored codes in the BCM or the CEM first, and repair those before anything else
- 2Check that the brake light switch is fitted correctly and that the brake pedal position sensor is seated properly. Also check that the fuses are intact
- 3Check the connectors to the brake light switch and brake pedal sensors for oxidation, breaks or chafed wiring
- 4If you have a diagnostic tool, read the brake pedal position values in live data and check that they follow each other when the pedal is pressed and released
- 5After the repair, brake normally and clear the code. The counter resets at every correct braking
- 6Do not work on the braking system yourself; have a workshop carry out the checks that need diagnostic equipment
Symptoms you may notice3
- Red warning symbol and message in the display
- Cruise control does not engage
- Warning symbol and message in the display
What the fault can affect1
- Cruise control is switched off while the fault is active
General guidance for car owners. Diagnosis on the car can point to a different cause.