VOLVO
ECM-4433 - Immobilizer, communication fault. Signal faulty. Permanent fault
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 engine control module (ECM) has registered a communication fault with the immobilizer, the locking system that makes sure the engine can only be started with the correct key. The fault is permanent, so it is still present when you read the code. The code is set in the engine control module.
Possible causes
- Signal wire shorted to supply voltage
- Signal wire shorted to ground
- Break in the signal wire
- Defective immobilizer
- Defective engine control module
What you can do
- 1Read off and note the fault code, erase it and check straight away whether it comes back
- 2Check that the harness between the engine control module and the immobilizer is not chafed, pinched or damaged
- 3Check that the connectors in the wire are firmly joined and free from oxidation
- 4Have a workshop with diagnostic equipment check the immobilizer and the engine control module, as they may need programming or replacement
Symptoms you may notice1
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.