Lambda sensor/lambda sensor deactivation
A lambda sensor is a sensor located in the exhaust of a gasoline engine and as of about 2016 in diesel engines. The probe measures the proportion of oxygen in the exhaust gas and transmits it to the engine management software. The lambda sensor is an instrument for measuring whether the combustion is burning too rich or too poor.
Depending on this lambda measurement value, the engine management software adjusts the ratio of fuel to air by changing the injection time of the injectors.
Starting around the year 2000, most cars have a second lambda sensor placed behind the catalytic converter to monitor its effectiveness. After installing a sport catalytic converter or downpipe, the value at the 2nd lambda sensor changes, in these models it is necessary that the lambda sensor is deactivated or modified software-wise to prevent error messages and emergency running.
Also with a standard catalytic converter which (sometimes) gives a malfunction on the lambda sensor and the repair costs no longer outweigh the cost of replacement or if it has already been replaced but still gives a malfunction, deactivating the second probe can be a solution.
Known error codes on the lambda sensor: