Test Description
WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers in the diagnostic procedure.
- 2
This step determines if the condition is active. The Powertrain Control Module (PCM) grounds the Alternative Fuel (AF) enable circuit when operating on CNG. - 4
This step tests for a short to ground on the AF enable circuit. The test light should not illuminate with the ignition off.