VOLVO
ECM-1808 - Camshaft position (CMP) sensor / engine speed (RPM) sensor Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The ECM compares the signal from the camshaft sensor with the signal from the engine speed sensor and checks that it lies within a reasonable range. If the camshaft sensor signal does not match what is expected, fault code ECM-1808 is set.
Possible causes
- Signal wire short-circuited to voltage
- Signal wire short-circuited to ground
- Open circuit in the signal wire or the supply wire
- Camshaft or engine speed sensor incorrectly installed
- Defective camshaft position sensor
- Defective engine speed sensor
What you can do
- 1Switch off the ignition and check the camshaft sensor connector for play and oxidation
- 2With a multimeter, check that the signal wires from the camshaft and engine speed sensors have no break and are not shorted to ground or voltage
- 3Check that the camshaft and engine speed sensors are correctly mounted and not loose
- 4If you have a diagnostic tool: check in live data that the camshaft sensor signal follows engine speed with the engine idling
- 5If the fault remains, have a workshop replace the camshaft or engine speed sensor, depending on which is at fault
Symptoms you may notice1
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.