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 MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 9 (BODY CONTROL MODULES)DIAGNOSING INTERMITTENTSTROUBLE SHOOTING INTERMITTENTSPOSSIBLE CAUSES & CORRECTIONS
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8
Possible Causes & Corrections
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Possible Causes & Corrections
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
Use following procedures to determine possible causes of intermittent MIL operation:
- Check for poor mating of one connector to another. Terminals may not be fully seated. Check for improperly formed or damaged terminals. Check wire-to-terminal connections.
- Check for poor connection from ignition coil to ground or arcing at spark plug wires or plugs.
- Check for poor connections at Powertrain Control Module (PCM) ground terminals.
- Check for electrical system interference caused by defective relay, PCM-driven solenoid or switch, which may cause sharp electrical surge. This type of problem will normally occur when problem component is operated.
- Check for aftermarket parts which may not have been produced to manufacturer's specifications. Solenoids without original equipment diodes for circuit protection or voltage regulators using transistors instead of silicone-chip circuitry may cause voltage surges (up to 300 volts) in PCM wiring, causing temporary PCM shutdown. PCM shutdown is a normal response to system over voltage (over 16 volts on most models). PCM powers when problem ceases to be present. A rapid shutdown and re-power could cause a flickering MIL with no DTCs set in memory.
- Check for improper installation of electrical accessories such as auxiliary lights, cell phones or 2-way radios.
- Ensure ground wire from PCM to distributor or ignition module is connected to a good ground.
- Check for intermittent short to ground on data circuits of data link connector or in MIL circuit. See ENGINE PERFORMANCE article in WIRING DIAGRAMS.
- On vehicles not equipped with a driver information center, use scan tool to check for intermittent wiring problem. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
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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.