VIN L

Intake Air Heater System Description

Intake Air Heater

The intake air heater is an electric heating element that heats the air as it is drawn into the engine intake manifold during cold weather operation. The glow plug control module controls and monitors the intake air heater control circuits. The engine control module (ECM) sends commands to the glow plug control module to enable or disable the intake air heater when certain conditions met. The glow plug control module monitors the voltage and feedback circuits of the intake air heater to verify proper operation.

A normal functioning system operates as follows:

* Engine coolant temperature is below 40°C (104°F).
* Barometer pressure, engine coolant temperature, engine run time, and battery voltage are calculated by the ECM to determine the required duty cycle of the intake air heater.
* The engine control module (ECM) will send a serial data message requesting intake air heater operation to the glow plug control module.
* The intake air heater receives the ON command from the glow plug control module and current flows through the heater element.
* The intake air heater will stay energized for up to 700 seconds or until the intake air temperature reaches 29.8°C (85°F).
* The ECM monitors the engine coolant temperature and once the temperature is above 49.9°C (121°F), the ECM sends a signal to the glow plug control module to turn OFF the intake air heater.