The catalyst monitor sensor is a non-linear characteristic type sensor fitted to the catalytic
converter. The PCM uses this as it's secondary sensor to measure the oxygen content of the
exhaust system gasses within the exhaust after they have passed through the catalytic
converter. As well as providing additional closed-loop fuelling control, the PCM uses this
information to determine the efficiency of the catalytic converter.
ECT sensor
The ECT sensor is screwed directly into the coolant outlet connector and measures the
temperature of the engine coolant rather than the cylinder head temperature. This is a
more accurate measurement of the engine temperature and the information is used by the
instrument cluster for the temperature gauge indication. It is also used by the PCM to
calculate fuel injection timing and period of injection which will vary dependant on the
engine temperature.
IMT valve
The IMT valve controls the position of the swirl plates located in the intake manifold.
The IMT valve is controlled by a vacuum operated solenoid which is located on top of the
intake manifold. The IMT valve is adjusted by the solenoid to the desired settings
determined by the PCM.
PCM