Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The intake air (IA) heater is located in the air inlet tube and is used to warm the incoming air to aid in starting the engine and for proper cylinder combustion. The glow plug control module (GPCM) will command the IA heater ON when the engine coolant temperature is below 40°C (104°F). The power to the IA heater is supplied by the battery positive voltage circuit. The IA heater is connected to the GPCM by the following circuits:
- The IA heater temperature signal circuit
- The IA heater command 1 circuit
- The IA heater command 2 circuit
- The IA heater voltage signal circuit
- The IA heater current signal circuit
- The IA heater feedback signal circuit
If there is a fault on any of these circuits, a DTC will set.