VOLVO
ECM-740C - Communication, central electronic module (CEM). 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 checksum the ECM calculates does not match the one stored in the CEM. The reason is one or several codes logged in the CEM. The fault applies to the C30, C70 (06-), S40 (04-) and V50.
Possible causes
- One or several codes are logged in the CEM
What you can do
- 1Read the codes in the central electronic module first and remedy them
- 2Clear the stored codes in the CEM once they have been remedied, then clear this code in the engine control module
- 3If you have a diagnostic tool: check that the CEM has no stored codes left before road testing the car
- 4If the code returns, have a workshop with diagnostic equipment check the CEM and the engine control module
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.