VOLVO
CEM-3F84 - Immobilizer signal. Faulty signal
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
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 CEM receives a signal from the gearbox that park or neutral is engaged, and a signal about the gear position sensor's position from the TCM over the CAN network. If they do not match, the code is set. The gear selector may then stay jammed in position P.
Possible causes
- A break, or a short to supply voltage, in the wire from the gear position sensor
What you can do
- 1With the ignition off, check that the connectors at the gear position sensor and the CEM are seated and not corroded or chafed
- 2Use a multimeter to check that the cable from the gear position sensor has no break and no short to battery plus
- 3With a diagnostic tool, follow the gear position sensor position in live data while you move the gear selector
- 4After the work, clear the code and check that the gear selector can be moved out of position P
Symptoms you may notice1
- The gear lever is stuck in P
General guidance for car owners. Diagnosis on the car can point to a different cause.