VOLVO
CEM-8A31 - Daytime running lamps, right. Faulty signal
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 CEM feeds the right-hand daytime running lamp from its own output. If the current drawn on that output is too high, the signal wire to the daytime running lamp is probably in contact with ground, and the output is then switched off after repeated faults until the code is cleared.
Possible causes
- The signal wire to the daytime running lamp is short-circuited to ground
What you can do
- 1Check that the daytime running lamp fuse is intact and that the lamp is firmly seated in its holder
- 2With the ignition off and the connector to the CEM unplugged, use a multimeter to check that the right daytime running lamp wire has no contact with ground (the body)
- 3Look for chafing and pinched areas on the wire, especially at the headlamp and where it enters the wiring harness
- 4Clear the code and start the car to see whether the fault comes back
- 5If the fault comes back, have a workshop with diagnostic equipment check the wiring and the module
Symptoms you may notice1
- The daytime running lamp does not work
What the fault can affect1
- The output to the right daytime running lamp is switched off permanently after repeated faults, until the code is cleared
General guidance for car owners. Diagnosis on the car can point to a different cause.