Theory Of Operation

The Intake Air Heater is integrated into the intake manifold cover. The Intake Air Heater element is used to heat the air coming into the Intake Manifold. This is done to help engine starting and improve driveability with cool or cold outside temperatures. Electrical supply for the air heater element is controlled by the Powertrain Control Module (PCM) through the Intake Air Heater Relay. One heavy duty cable connects the air heater element to the Intake Air Heater Relay. This cable will supply 12 volts to the air heater elements. The PCM will illuminate the MIL lamp after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL lamp when the diagnostic runs and passes in four consecutive drive cycles.