VOLVO
BCM-0020 - Right front wheel sensor. Signal missing
System
Brake Control Module (BCM)
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:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (11)
- Volvo S60 (2001–2009)2002–2009
- Volvo S80 (1999–2006)2002–2006
- Volvo V70 (2000–2008)2002–2008
- Volvo V70 XC / XC70 (2001–2007)2002–2007
- Volvo XC90 (2003–)2003–2004, 2015
- Volvo XC90 (2003–)2005–2006All engines except: B8444S
- Volvo XC90 (2003–)2007Engine B5254T2, D5244T4 only
- Volvo XC90 (2003–)2008–2010All engines except: B6324S, B8444S
- Volvo XC90 (2003–)2011All engines except: B6324S5, B8444S
- Volvo XC90 (2003–)2012All engines except: B6324S5
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
What does this fault code mean?
The brake control module (BCM) receives wheel speed information from the wheel sensors, which read a toothed ring on the wheel axle. The code is set if the signal from the right front wheel sensor is disturbed or drops out many times. It can only be diagnosed while the car is rolling, so it is usually seen then.
Possible causes
- Contact resistance in the connections
- Open circuit, or short to ground or supply voltage, in the sensor supply
- Signal wires shorted to each other
- Signal wire shorted to ground or supply voltage, or with an open circuit
- Defective wheel sensor
- Internal fault in the control module
What you can do
- 1Check the connectors at the brake control module and the wheel sensor for contact resistance and oxidation
- 2Read the wheel speed with diagnostic equipment while the wheel is turned; if the value updates, the fault was a poor connection
- 3Check the wire between the brake control module and the wheel sensor, especially near the steering column, for damage and chafing
- 4Clear the code and road test to see whether it returns
- 5The brake system is safety critical: drive carefully until the fault is fixed, and do not work on ABS or the brakes yourself
Symptoms you may notice4
- The general warning lamp and ABS warning lamp come on
- The brake circuit does not work and the warning lamp comes on
- Traction control, stability control and anti-skid do not work
- With an intermittent fault the ABS lamp may only go out some way into the next drive
What the fault can affect3
- ABS is disabled
- Electronic brake force distribution (EBD) is disabled if two or more wheel sensors have failed
- Traction control, stability control, active yaw control (AYC) and brake assist are disabled
General guidance for car owners. Diagnosis on the car can point to a different cause.