VOLVO
ECM-850C - 5 volt power supply. 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 engine control module (ECM) monitors the internal voltage circuits that feed the components, and the code is set when the voltage in one circuit is too high. The check runs with the ignition on. The fault can lie in a sensor, in the wire feeding it, or in the control module itself.
Possible causes
- Voltage cable to a sensor shorted to voltage
- Damaged sensor
- Damaged engine control module (ECM)
What you can do
- 1Read the code, clear it and road test the car to see whether it comes back
- 2Check the sensor voltage cable for chafing and contact with voltage; use a multimeter to check that the cable has no contact with battery voltage
- 3Check the sensors on the same circuit for damage and poor contact
- 4If you have diagnostic equipment, read the sensor values in live data with the ignition on; a sensor showing a too-high value points to where the fault is
- 5If the code does not clear, have a workshop decide whether the control module needs replacing
Symptoms you may notice3
- Poor performance
- The engine misfires
- The engine is hard to start
General guidance for car owners. Diagnosis on the car can point to a different cause.