VOLVO
CEM-4A31 - Ejector sensor. 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 sensor on the ejector side reads the fuel level of one tank. The CEM registers that the fuel level has not changed for a long time although the tank holds fuel. The trip computer may then show an empty tank too early, and the fuel gauge may show zero.
Possible causes
- The ejector side sensor is faulty
What you can do
- 1Check that the ground wire to the sensor is tight and clean. Use a multimeter to check that it has no break
- 2The fault shows only when there is a reasonable amount of fuel in the tank, so top up a little if the tank is nearly empty
- 3If the fault remains with an intact ground wire, have a workshop replace the fuel level sensor on the left side, since it sits in the tank
- 4After the work, clear the code and check that the fuel gauge shows the correct level
Symptoms you may notice2
- The trip computer displays an empty tank too early
- The fuel gauge reads zero although the tank holds fuel
General guidance for car owners. Diagnosis on the car can point to a different cause.