VOLVO
CEM-8F21 - Wipers. Signal too high/Signal missing. Intermittent fault
System
Central Electronic Module (CEM)
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–)
What does this fault code mean?
The fault is intermittent: the position of the wipers and the position of the wiper switch did not match on an earlier occasion, but the fault is no longer present. The wipers may then run only at the lowest speed.
Possible causes
- A fault in the switch that signals operating or rest position, such as a short or open circuit
- Defective windscreen wiper lever
- Defective fuse for the wiper control
What you can do
- 1Clear the code and check whether it returns with the ignition on
- 2Look for chafing and an intermittent short in the wire between the CEM and the steering wheel module (SWM)
- 3Check that the connectors to the wiper lever and the steering wheel module are firmly seated and clean
- 4Check the fuse for the wiper control
- 5If the fault returns, have a workshop replace the wiper lever
Symptoms you may notice1
- The windscreen wipers only run at the lowest speed
What the fault can affect1
- Only the lowest wiper speed works
General guidance for car owners. Diagnosis on the car can point to a different cause.