VOLVO
EFI-0044 - Ignition coil. Faulty signal
System
Electronic Fuel Injection (EFI)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
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 code is stored when, with the engine on a lean mix, the crankshaft sensor reads an engine speed that is abnormal because of misfires. The fault can therefore lie in the ignition coil or the circuit to it. Spark plugs can give the same symptoms, so they should be checked together with the coil.
Possible causes
- The ignition coil is defective
- The spark plugs are defective
- Short to earth or to a live supply in the ignition wiring
- Open circuit in the ignition system circuit
- Contact resistance at the connections
What you can do
- 1Check the plugs on each coil and on the control module for play and oxidation
- 2Find the misfiring cylinder by unplugging the ignition coils one at a time with the engine running
- 3Replace the spark plug in the misfiring cylinder with a new one, or swap the coil there, and road test
- 4Use a multimeter to check whether the wiring to the affected ignition coil has a break or is shorted to earth
- 5Avoid touching ignition coils and plug leads while the engine runs, as the high-voltage circuit is dangerous
- 6If the fault does not clear, have a workshop with diagnostic equipment check the whole ignition system
Symptoms you may notice4
- Emissions warning lamp is lit
- Engine may stall
- Poorer performance
- Uneven idle
What the fault can affect1
- The engine runs only on a rich fuel/air mixture
General guidance for car owners. Diagnosis on the car can point to a different cause.