[YesYes]

Катализатор... лямда... -для них свои ошибки есть.
Чего гадать?
Надо рыть по p0171:
- Failed intake air temperature sensor
- Failed air flow sensor
- Failed injector
- Air drawn in from gaps in gasket, seals, etc.
- Failed engine coolant temperature sensor
- Failed barometric pressure sensor
- Failed manifold absolute pressure sensor
- Exhaust leak
- Incorrect fuel pressure
- Harness damage in injector circuit or loose connector contact
- Failed engine-ECU