VOLVO
ECM-1804 - Boost pressure 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?
Before the engine starts, the ECM checks the boost pressure sensor against the atmospheric pressure sensor. If the pressure difference between the two is too large, fault code ECM-1804 is set, and the boost pressure sensor is then the most likely cause.
Possible causes
- Defective boost pressure sensor
What you can do
- 1If you have a diagnostic tool: read the boost and atmospheric pressures with the ignition on, and check that the difference between them is not large
- 2Switch off the ignition and check the boost pressure sensor connector for play, contact resistance and oxidation, then reconnect it
- 3If the difference is still large with a sound connector, the boost pressure sensor is probably defective
- 4If the fault remains, have a workshop replace the boost pressure sensor
Symptoms you may notice1
- The engine feels sluggish
What the fault can affect1
- The control module uses a fixed value for boost pressure
General guidance for car owners. Diagnosis on the car can point to a different cause.