Inlet manifold PTC heater	general information and component renewal
General infomation
	The system incorporates the manifold PTC (Positive Temperature Coefficient) heater, the relay and the coolant temperature sensor.
	When the ignition is switched on and the engine is cold (coolant below 50 deg C), the relay- energising current is supplied by the engine management ECU, which then closes the relay contacts and allows current to flow from the battery to the heater.
	This ensures that the inlet manifold is warm enough, even before the effect of the coolant heating becomes apparent, to prevent fuel droplets condensing in the manifold, thus improving driveability and reducing exhaust emissions when the engine is cold.
	As soon as the engine warms up to temperatures above 50 deg C, the ECU switches off the supply current, and the relay cuts off the power supply to the manifold heater.
	If the engine suddenly develops flat spots when cold, the system may be faulty.
Component renewal
PTC heater
	The PTC heater is fitted to the underside of the inlet manifod, and access to the heater is strictly limited. Therefore, to remove the heater, it will first be necessary to remove the inlet manifold as described in Section 15. With the manifold on the bench, using circlip pliers, remove the circlip and withdraw the heater.
	Inspect the rubber sealing ring for signs of damage or deterioration, and renew if necessary.
	On refitting, ensure that the heater locating projection is correctly engaged in the manifold recess, then secure the switch in position, with its circlip. Refit the manifold to the car as described in Section 15.
PTC heater relay
	The manifold PTC heater relay is an integral part of the relay module, and can be removed and refitted as described in Section 13.