VOLVO
CEM-1A22 - Engine control module (ECM). Signal too high
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 checks the start signal to the ECM and has registered that the signal is too high. The fault code is set when the signal wire is short-circuited to supply voltage. The fault is not visible to the driver.
Possible causes
- Signal wire short-circuited to supply voltage
What you can do
- 1With a diagnostic tool, read the start-signal status and change the key position; if it stays the same, the fault is permanent
- 2Check that the connectors at the CEM are secure and clean
- 3Check with a multimeter that the signal wire has no voltage when the ignition is off and the connector is disconnected
- 4If the fault remains, have a workshop continue the fault-tracing
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.