VOLVO
ECM-800D - System relay. Signal too low
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. Once the relay has been activated, the fault code is set if the voltage from it is too low. The cause may be contact resistance, a break in the signal wire or a damaged relay, and the engine will then not start. The fault applies to the C30, C70 (06-), S40 (04-) and V50.
Possible causes
- Contact resistance in the connections
- Open circuit in the signal wire to the system relay
- Damaged system relay
What you can do
- 1Read the code, clear it and road test to see whether it comes back
- 2Check whether the connectors to the system relay are loose, corroded or making poor contact
- 3Check the signal wire for an open circuit, using a multimeter if you have one
- 4If the fault remains, 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.