Description

Lambda Sensor – Rear (post-catalyst oxygen sensor) for the exhaust and engine management system of the 4.2L V8 Supercharged and 4.4L V8 petrol engines.

The sensor mounts in the front pipe and catalyst assembly, downstream of the catalytic converter. Unlike the pre-catalyst sensor it does not trim fuelling directly: the engine control module compares its output against the upstream sensor to assess catalyst conversion efficiency and to set the associated emissions monitor.

The unit is heated so that monitoring becomes active shortly after a cold start. It is not serviceable and is replaced complete.