inCarDoc
posted this
20 March 2019
- Last edited 25 August 2020
Description
Indicates that front oxygen sensor (at the input of catalytic converter) detects lower 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.
Symptoms
- Check Engine dashboard light is ON
- Possible lack of power and car dynamic
- Possible increase of fuel consumption
- Possible misfire issues
- Unstable work and sound from engine: stumbles, shakes
Causes
- Faulty or dirty mass air fuel (MAF) sensor
- Dirty or "oiled" air filter
- Faulty fuel regulators or injectors
- Vacuum leak
- Worn-out spark plugs
- Faulty oxygen sensor
- Faulty coolant system or thermostat
Severity - moderate
Does not have immediate danger effect to the car or driver, but at longer period could lead to engine overheating and possible damage. Increasing environment pollution.
Troubleshooting
- Check and clean MAF and oxygen sensors
- Inspect vacuum and fuel pipes
- Inspect and replace, if required, air filter
- Inspect and replace, if required, fuel pressure regulators or pump
- Inspect and replace, if required, coolant sensors or thermostat
- Inspect and replace, if required, spark plugs