VOLVO
ECM-800C - System relay. 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 ECM tests how the system relay works. The fault code is set when the module senses voltage from the relay even though the relay is switched off. The cause may be a power wire shorted to supply voltage, or a damaged system relay. The fault applies to the C30, C70 (06-), S40 (04-) and V50.
Possible causes
- The power wire is shorted to supply voltage
- Damaged system relay
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Inspect the power wire to the system relay for chafing, pinching and places where it may have touched a live wire
- 3Using a multimeter, check whether the wire carries voltage when the ignition is off
- 4If no fault is found, have a workshop try a new system relay
Symptoms you may notice1
- Starting problems: the engine does not start, sometimes or all the time
General guidance for car owners. Diagnosis on the car can point to a different cause.