VOLVO
ECM-801B - System relay. Signal missing
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 engine control module checks the system relay and has registered that the voltage on the relay's signal wire is too low. The fault may be a signal wire shorted to ground or a damaged system relay.
Possible causes
- Signal wire shorted to ground
- Damaged system relay
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Look at the connectors on the system relay: are they secure and clean?
- 3Using a multimeter, check that the signal wire is not shorted to ground
- 4If you have a diagnostic tool: read the voltage on the system relay signal wire with the ignition on
- 5If no fault is found, have a workshop try a new system relay
Symptoms you may notice1
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.