Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1997CHEVY EXPRESS G3500, VAN CARGO, 6.5 FREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 93 (INSTRUMENT PANEL (P SERIES))SYSTEM TESTSSPEEDOMETER ALWAYS READS ZERO OR IS INACCURATE (COMMERCIAL)
1997 Chevrolet Chevy Express G3500, Van Cargo, 6.5 F
Speedometer Always Reads Zero Or Is Inaccurate (Commercial)
1997 Chevrolet Chevy Express G3500, Van Cargo, 6.5 FSECTION Speedometer Always Reads Zero Or Is Inaccurate (Commercial)
WARNING: This page is about a different car, the 1997 GMC Vandura, 1997 GMC Forward Control, 1997 Chevrolet Forward Control, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect instrument cluster harness connector. Disconnect Vehicle Speed Sensor (VSS) buffer harness connector (diesel engine) or Vehicle Control Module (VCM) harness connector (gasoline engine). Using ohmmeter, measure resistance between Dark Green wire terminals of VSS or VCM harness connector and instrument cluster harness connector terminal No. 28. If resistance is more than one ohm, repair open in Dark Green wire. If resistance is less than .5 ohm, go to next step.
- Measure resistance between instrument cluster harness connector terminal No. 28 (Dark Green wire) and ground. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire.
- Measure voltage between instrument cluster harness connector terminal No. 28 (Dark Green wire) and ground. If voltage is more than one volt, repair short to voltage in Dark Green wire. If voltage is less than one volt, problem is in VSS or VCM. See appropriate TESTS W/CODES
article in ENGINE PERFORMANCE section:
- TESTS W/CODES - 5.7L
- TESTS W/CODES - 6.5L - Diesel
- TESTS W/CODES - 7.4L
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.