VOLVO
ECM-552C - Oil temperature sensor. 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)
What does this fault code mean?
Although the code is named signal too high, it applies to a mismatch between the oil and coolant temperature readings. The engine control module (ECM) compares them and sets the code when the gap becomes too large. The reading is also used to calculate the service interval, so the fault can affect the service indication. The code is set after the car has stood for a long time and then been driven.
Possible causes
- Signal wire shorted to voltage
- Damaged oil temperature sensor
What you can do
- 1Clear the code and drive the car after it has stood for a long period, to see whether it returns
- 2Make sure the connectors at the oil temperature sensor and the engine temperature sensor are fully seated and free from oxidation or raised contact resistance
- 3With a multimeter, check that the oil temperature sensor's signal wire has no contact with ground or voltage
- 4With a diagnostic tool, compare oil and coolant temperatures in live data, cold and warm, and see whether the gap is unreasonable
- 5If the fault remains, have a workshop check the wiring and replace the oil temperature sensor if needed
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.