VOLVO
CEM-3F81 - Immobilizer signal. Signal too high. 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?
This variant covers intermittent faults on the transistor stage to the starter relay. The fault is intermittent, so it may have occurred before without being active now. The usual cause is an output shorted to plus. The engine does not start.
Possible causes
- The output signal from the transistor stage to the starter relay is shorted to plus
What you can do
- 1With the ignition off, check that the starter relay is firmly seated and its contacts are clean
- 2Use a multimeter to check that the signal wire to the starter relay is not shorted to plus
- 3If the fault returns, have a workshop check the CEM, since the transistor stage is inside the module
- 4After the work, clear the code and check that the engine starts
Symptoms you may notice1
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.