VOLVO
CEM-4C02 - Outside temperature sensor. Signal too low
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CEM reads the outside sensor in the left mirror. If the signal is too low, the code is set, usually because of a short to ground. The outside temperature gauge then shows a wrong value or does not work.
Possible causes
- Short to ground
What you can do
- 1With the ignition on, compare the outside temperature in the display with the actual conditions. If it is wrong, the fault is probably permanent
- 2Look at the sensor in the left door mirror and check that it is not damaged, dirty or covered
- 3Check that the connectors in the sensor wiring are seated and not corroded
- 4Have a workshop check the wires for a short to ground, since this needs trim removed
- 5After the work, clear the code and check that the outside temperature is shown correctly
Symptoms you may notice1
- The outside temperature gauge does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.