Code 72, VSS CKT Loss Transmission Output Signal - Diesel: Notes
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For Code 72 coverage on gasoline models, see appropriate G - GASOLINE TESTS W/ CODES article in the ENGINE PERFORMANCE section. See below.
VSS output sensor is a magnetic induction type. Gear teeth pressed on outside diameter of output carrier assembly induce an alternating current in sensor when drive wheels are turning.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Test verifies VSS voltage at PCM.
- Test checks VSS buffer ground circuit.
- Test checks VSS circuit at buffer module.
- Test verifies VSS signal at sensor.