VOLVO
CEM-8F1D - X-supply relay circuit. Short-circuit to supply voltage
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 monitors the voltage of the driver outputs that feed the 15-supply and the headlamp range control. If one of the outputs is shorted to supply voltage, the fault is recorded and the automatic headlamp range control may stop working.
Possible causes
- Signal wire to the left headlamp range motor shorted to supply voltage
- Signal wire to the right headlamp range motor shorted to supply voltage
- Supply wire to one of the headlamp range motors shorted to supply voltage
- Supply wire to other connected units, such as the brake control module (BCM), heated seats or the brake vacuum pump, shorted to supply voltage
- Fault in the signal wires between the ignition switch and the CEM, or an internal fault in the ignition switch
- Internal fault in the 15-supply relay in the CEM
What you can do
- 1Clear the code and check whether it returns when the ignition is switched on
- 2Look for chafing on the signal and supply wires to the headlamp range motors in the left and right headlamps
- 3With the ignition off, use a multimeter to check that the signal wires to the range control carry no voltage
- 4If you have a diagnostic tool, activate the range control and check that the motors move
- 5If the fault remains after these checks, have a workshop trace the wiring and remedy the fault
Symptoms you may notice3
- The beam height control does not work
- The automatic headlamp range control does not work
- Low beam is set incorrectly
General guidance for car owners. Diagnosis on the car can point to a different cause.