Fuel system
Lambda (oxygen) sensor
Measures exhaust oxygen to fine-tune the mixture (fuel injection).
How it works
Positioned in the exhaust, the lambda (oxygen) sensor tells the ECU whether the mixture is too rich or too lean, to optimize both consumption and emissions. A dead sensor makes the injection system run in limp mode (often too rich), leading to excess fuel consumption and a check-engine light.
Maintenance tips
- A diagnostic tool can read its status.
- Avoid dubious fuel additives that can foul it.
Related symptoms
⚠️ The information on this page is provided for educational purposes to help you understand the role and operation of the part. It replaces neither a physical inspection nor the judgment of a certified mechanic. Before any work on a safety-critical component (braking, steering, transmission, suspension), have the part's condition confirmed by a professional.