VOLVO
BCM-C002121 - Brake Booster Performance. General Signal Failures. Signal too low
System
Brake Control Module (BCM)
Volvo models this fault code applies to
Applies to the following models:
1 modelV60 (2011–)
Show models by year and engine (2)
What does this fault code mean?
On the V60, the brake control module (BCM) has received too low a signal from the pressure and temperature sensor in the brake system. The sensor measures the pressure in the hydraulic system, and when the requested brake pressure does not match the measured pressure, the module cannot control the brake booster correctly. Assistance functions may then be unavailable.
Possible causes
- Damaged wire or connector to the sensors
- Incorrect or loose connection at the pedal, vacuum or pressure sensor
- Damaged pressure or vacuum sensor
- Air in the brake fluid
- Mechanical fault in the brake booster
What you can do
- 1Read and note the code, clear it and road test the car to see whether it returns
- 2Make sure there are no air bubbles in the brake fluid
- 3Check that the sensor wiring is undamaged and that the connectors are secure and free from oxidation
- 4Read the sensors with diagnostic equipment and replace any damaged components
- 5The braking system is safety critical: do not work on the brake booster or sensors yourself, and let a workshop decide when the car can be driven normally
Symptoms you may notice4
- Traction control does not work
- Hill descent assist does not work
- Hill start assist does not work
- Front monitoring and adaptive cruise control do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.