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 MANUALSGMC1995FORWARD CONTROL 4.3 Z, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)TRANSMISSIONAUTOMATIC TRANSAUTOMATIC TRANSMISSION DIAGNOSIS - 4L80-EDIAGNOSTIC CHARTS - GASOLINEDTC 72, VSS CIRCUIT LOSS TRANSMISSION OUTPUT SIGNALNOTES

1995 GMC Forward Control 4.3 Z, Standard

DTC 72, VSS Circuit Loss Transmission Output Signal: Notes

1995 GMC Forward Control 4.3 Z, StandardSECTION Notes

Fig 1: DTC 72 - Circuit Diagram (Gasoline)

Courtesy of GENERAL MOTORS CORP.

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 control module.
Test checks VSS buffer ground circuit.
Test checks VSS circuit at buffer module.
Test verifies VSS signal at sensor.

Fig 2: DTC 72 - Troubleshooting Chart (Gasoline)

Courtesy of GENERAL MOTORS CORP.

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.