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 MANUALSCHEVROLET1993SPORTVAN G30, VAN PASSENGER, 7.4 NREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 24 (ENGINE CONTROLS - TESTS W/CODES - 6.5L DIESEL)DIAGNOSTIC TROUBLE CODE CHARTSDTC 29 - GLOW PLUG RELAY CIRCUIT FAULTTEST
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 N
DTC 29 - Glow Plug Relay Circuit Fault: Test
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 NSECTION Test
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Rally Camper Special, 1994 GMC Rally, and 1994 GMC Forward Control. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This step determines if DTC 29 is the result of a hard failure.
- Scan tester may not display system voltage. It is important that the PCM is cycling voltage on and off indicating the PCM is okay.
- This step checks the relay feed circuit.
- This step checks the relay ground.
- This step will determine if an open is present in the glow plug relay control circuit.
- This step checks the relay and wiring.
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.