Test Description

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

2) - This step tests for a inoperative mode actuator in one mode positions or in the wrong mode positions.
3) - This step tests for a inoperative recirculation actuator in one mode positions or in the wrong mode positions.
4) - This step tests A/C system performance that is correct for the current conditions. that would mandate a state of automatic recirculation mode being active. The automatic recirculation mode becomes active when the A/C high side pressure reaches 2206-2620 kPa (320-380 psi). The mode remains ON until the high side pressure drops below 1447-1861 kPa (210-270 psi). In automatic recirculation mode the HVAC controller does not indicate that the mode is active. The outside air (OSA) and the recirculation (RECIRC) switches and indicators are inoperative on the HVAC controller.
8) - This step tests for an A/C high pressure recirculation switch, which is internally shorted and which causes the automatic recirculation mode to be active.

Fig 1: Air Recirculation Malfunction Diagnosis (Steps 1-7)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Air Recirculation Malfunction Diagnosis (Steps 8-15)

Courtesy of GENERAL MOTORS CORP.