VOLVO
CRM-20C2 - Hall sensor 18. Short to GND, disconnected or internal error
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 18 draws more current than normal, and no sensor pulse appears when the pump runs. The fault can be caused by the signal wire being shorted to ground, an open connection to the control module, or an internal fault in the sensor or in the roof control module.
Possible causes
- The signal wire is shorted to ground
- Open connection between hall sensor 18 and the roof control module
- Internal fault in hall sensor 18
- Internal fault in the roof control module (CRM)
What you can do
- 1Read out and clear the fault code, test the roof and see whether the fault returns
- 2Check that the connector at hall sensor 18 is clean, fully seated and free from loose connections
- 3With a multimeter you can check that the wire from the sensor has no break and no short to ground
- 4A damaged wire may be the cause and can be repaired. Otherwise a workshop should replace hall sensor 18
- 5If the fault remains, a workshop needs to look at the roof control module
Symptoms you may notice2
- No or limited roof operation
- Message in the text display
General guidance for car owners. Diagnosis on the car can point to a different cause.