VOLVO
EFI-0025 - Atmospheric pressure sensor. 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 control module receives a faulty signal from the atmospheric pressure sensor, which measures the ambient air pressure. The fault may be a defective sensor, contact resistance, or a short-circuit or open circuit in the signal wire, and it can cause uneven idle.
Possible causes
- Defective atmospheric pressure sensor
- Signal wire short-circuited to ground or supply voltage
- Open circuit in the signal wire
- Contact resistance
What you can do
- 1Make sure the connectors to the sensor are secure and clean. Look for oxidation and loose connectors.
- 2If you have a diagnostic tool, read the sensor value in live data with the ignition on. A value that does not change at all is a clear warning sign.
- 3Look for damage to the sensor and its wiring, and use a multimeter to check that the signal wire is not broken or short-circuited.
- 4If there is no fault in the wiring, the sensor needs replacing. Have a workshop do the replacement.
Symptoms you may notice2
- The malfunction indicator lamp lights up
- Uneven idle
General guidance for car owners. Diagnosis on the car can point to a different cause.