Indicates that front oxygen sensor (at the input of catalytic converter) detects higher than expected percentage of oxygen in exhaust gasses. Could be due to the unbalanced air-to-fuel proportion at the engine, fault oxygen sensor or other systems.
- Check Engine dashboard light is ON
- Possible lack of power and car dynamic
- Unstable work and sound from engine: stumbles, shakes
- Faulty or dirty mass air fuel (MAF) sensor
- Malfunctioning fuel pump
- Clogged fuel filter or injectors
- Vacuum leak
- Faulty oxygen sensor
- Leaks in exhaust system
Severity - moderate
Does not have immediate danger effect to the car or driver, but at longer period could lead to engine overheating and damage. .
- Check and clean MAF sensor
- Inspect vacuum and air intake systems for leaks
- Inspect and replace, if required, fuel filter
- Inspect and replace, if required, fuel pump
- Review and correct, if required, fuel injectors, exhaust system, other systems that have DTCs.