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 23 (ENGINE CONTROLS - TESTS W/CODES - 6.5L DIESEL)SELF-DIAGNOSTIC SYSTEMENTERING OR EXITING DIAGNOSTIC MODE
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 N
Entering Or Exiting Diagnostic Mode
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 NSECTION Entering Or Exiting Diagnostic Mode
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.
- With ignition on and engine off, connect a jumper wire between Data Link Connector (DLC) terminal "B" (diagnostic terminal) and terminal "A" (ground). See Fig 1. The Diesel Electronic Control (DEC) system will enter diagnostic mode.
- In this mode, PCM will display DTC 12 by flashing the MIL once, followed by a short pause, then 2 flashes in quick succession.
- DTC 12 will be displayed 3 times. If no other codes are stored, DTC 12 will continue to flash until diagnostic terminal is ungrounded. To exit diagnostic mode, turn ignition off and remove jumper from DLC.
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.