VOLVO
ECM-0005 - Engine coolant temperature (ECT) sensor. Faulty signal. Intermittent fault
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsS70 (1997–2000), S80 (1999–2006), V70 (1997–2000), V70 (2000–2008)
What does this fault code mean?
The engine control module receives an incorrect signal from the engine coolant temperature sensor. The code is set if the engine is cold at start and the temperature then does not rise as it should within a certain time. The fault is recorded as intermittent, so it may not be visible right now.
Possible causes
- Contact resistance in the sensor connector
- Break in the signal or earth wire
- The signal wire is shorted to supply voltage
- Faulty engine coolant temperature sensor
What you can do
- 1Check the sensor connector for contact resistance and oxidation. Clean it and make sure it is fully seated
- 2If you have a diagnostic tool, read the coolant temperature in live data when the engine is cold and again after some driving. The value should rise steadily
- 3Measure with a multimeter that the signal and earth wires to the sensor have no break and are not shorted to supply voltage
- 4Clear the fault code and road test the car. If it returns, have a workshop repair or replace the engine coolant temperature sensor
- 5Note whether the fault only appears when the engine is cold, so the workshop can reproduce it
Symptoms you may notice3
- High idle speed
- The cooling fan runs at half speed with the ignition on and the engine running
- The exhaust smokes on start-up
What the fault can affect1
- The engine control module uses a fixed value for the engine temperature instead of the actual reading
General guidance for car owners. Diagnosis on the car can point to a different cause.