Test Description

WARNING: This page is about a different car, the 1995 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Test numbers refer to numbers on diagnostic chart.

Code 29 will set if the PCM detects the wrong voltage potential. Test will determine if relay can be controlled by PCM.
This check can detect a partially shorted coil which would cause excessive current flow. Excessive current flow to a QDM will be detected as a fault and set a code.
The remaining checks will identify a circuit problem that has caused an excessive current flow or inoperative relay.

Fig 1: Code 29 Schematic (Corvette) Secondary Air Injection

Fig 2: Code 29 Diagnostic Flow Chart (Corvette) Secondary Air Injection