Enter the oxygen sensor, also called the lambda sensor, because it gives an indication of the ratio of air to fuel (called the lambda ratio) being consumed by the engine.

I recently had an engine fault light come on. I took the car to my local garage and they ran a diagnostic - it came up with a rear lambda sensor fault. ... While fitting a new lambda sensor to my ...

A faulty oxygen sensor can lead to premature damage to expensive parts of the engine system. When replacing an oxygen sensor, it’s important to use the same type as the original.” He recommends taking ...