Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
DTC indicates engine is running lean. Possible causes of a lean air/fuel mixture are:
- Vacuum leak.
- Fuel pressure low.
- Fuel quality poor or water in fuel.
- Exhaust manifold gasket leak or leak around HO2S1.
- Fuel injectors clogged.
- HO2S1 weak.
- ETC/IAT out of range.
- BARO voltage out of normal range.
- Valve timing.
To verify system is running lean, use scan tool to monitor HO2S1 and HO2S2. If both sensors are less than 300 millivolts, system is running lean and oxygen sensors are probably not at fault.