Test D: Insufficient, Erratic Or No Heat

PINPOINT TEST D: INSUFFICIENT, ERRATIC OR NO HEAT

D1:

D2-D5:

Normal Operation
During normal operation, when heat is selected on the temperature control selector and the blower motor switch is turned ON, the blower motor directs air through the heater core. The heater core is filled with heated engine coolant. The PCM activates the electric coolant pump as necessary to maintain adequate coolant temperature.

Possible Causes
- Electric coolant pump
- Engine cooling system
- Temperature control selector
- Temperature control cable