VOLVO
ECM-A20C - Engine control module (ECM). Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C30 (2007–2013)2008–2013Engine B5254T7 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo C70 (2006–2013)2008–2013Engine B5254T7 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The central electronic module (CEM) sends a timer value over the CAN network giving the time elapsed since the last engine shutdown. The engine control module relies on it when starting a warm engine. Although the name says signal too high, the code is set when the engine control module finds the signal wrong or missing, and the lamp comes on.
Possible causes
- Faulty timer signal from the central electronic module (CEM)
- Open or short circuit in the CAN cable between the engine control module and the CEM
- Damaged central electronic module (CEM)
What you can do
- 1Start by reading and remedying the fault codes in the central electronic module (CEM)
- 2Check the CAN cable between the engine control module and the CEM for open circuits, short circuits and chafing
- 3The fault code must not be cleared until the codes in the CEM and other affected modules have been remedied and cleared
- 4Clear the fault code once the faults are remedied and road test the car to see whether it returns
Symptoms you may notice1
- Malfunction indicator lamp lights
What the fault can affect1
- The engine control module calculates a timer value instead
General guidance for car owners. Diagnosis on the car can point to a different cause.