VOLVO
CRM-20B1 - Hall sensor 3. Shorted to supply
System
Chassis (Brakes, Steering, Suspension)
Volvo models this fault code applies to
Applies to the following models:
1 modelC70 (2006–2013)
Show models by year and engine (1)
What does this fault code mean?
Hall sensor 3 draws less current than normal, and when the hydraulic pump for the roof runs, no signal comes from the sensor. This mainly points to a short to voltage in the signal wire between the sensor and the control module. A damaged sensor or a fault inside the roof control module can also cause the code.
Possible causes
- Short to voltage in the signal wire from hall sensor 3
- Damaged hall sensor
- Internal fault in the roof control module (CRM)
What you can do
- 1Read out and clear the fault code, then test the roof in both directions and see whether the fault returns
- 2Check that the connector to hall sensor 3 is firmly fitted and free from corrosion
- 3With a multimeter you can check whether the signal wire has contact with voltage
- 4If no fault is found in the wire, a workshop may need to replace hall sensor 3
- 5If the fault remains, a workshop needs to check the roof control module
Symptoms you may notice2
- The roof cannot be operated, or only partly
- Message in the text display
General guidance for car owners. Diagnosis on the car can point to a different cause.