VOLVO
ECM-0171 - Long-term fuel trim, bank 1.Signal too high
System
Engine Control Module (ECM)
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:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
Fuel trim on bank 1 has become too lean according to the adaptive corrections, and the control module logs a fault when the corrections are too high. Possible causes include a damaged fuel pump or regulator, air entering the intake or vacuum system, a clogged fuel filter, or damaged injectors. A leak in the exhaust can also play a part.
Possible causes
- Damaged fuel pump or fuel regulator
- Air leak in the inlet manifold
- Leak in the vacuum system
- Dirty fuel filter
- Damaged injectors
- Leak in the exhaust system
What you can do
- 1Read the fault code, clear it and road test to see whether it returns
- 2Check that the intake hose and the vacuum hoses are tight and not cracked
- 3With the engine warm, listen for exhaust leaks and look for soot at the joints
- 4If you have a diagnostic tool, read the fuel adaptation values in live data at warm idle. Consistently high values confirm a lean mixture
- 5Have a workshop with diagnostic equipment check fuel pressure, the fuel pump and the injectors
- 6A dirty fuel filter can cause too little fuel, so have a workshop replace it if needed
Symptoms you may notice1
- Malfunction indicator lamp (MIL) lit
General guidance for car owners. Diagnosis on the car can point to a different cause.