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 MANUALSCHEVROLET1987STEP VAN P20, 7.4 W, AUTOMATIC, 400/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 31 (ENGINE CONTROLS - REMOVE/INSTALL/OVERHAUL)POWERTRAIN CONTROL MODULE (PCM)PROGRAMMABLE READ-ONLY MEMORY (PROM)REMOVAL
1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40
Programmable Read-Only Memory (Prom): Removal
1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40SECTION Removal
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.
- Remove PCM from vehicle. See REMOVAL under CONTROL UNIT . Position PCM so bottom cover is facing upward. Remove slide-off PROM access cover by depressing locking tab.
- Using PROM removal tool, grasp PROM at narrow ends. Gently rock PROM from end to end while pulling up. If installing new PROM, remove old PROM from PROM carrier.
NOTE:
Note reference notch locations in PROM, carrier and PCM for reassembly reference.
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.