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.

3) - This step determines if the air temperature door position is within the specified range of the commanded value.
6) - Tests for a short to voltage in the 5-volt reference circuit.

Fig 1: DTC B0408 Diagnosis (Steps 1-8)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC B0408 Diagnosis (Steps 9-15)

Courtesy of GENERAL MOTORS CORP.