Test Description

NOTE: Test numbers refer to numbers on diagnostic chart.

Code 27 will set if the PCM detects the wrong voltage potential. Test will determine if solenoid 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 solenoid.

Fig 1: Code 27 Schematic (Corvette) EGR Solenoid Valve

Fig 2: Code 27 Diagnostic Flow Chart (Corvette) EGR Solenoid Valve