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 MANUALSCHEVROLET1990CHEVY VAN G20, 4.3 Z, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEREMOVE, OVERHAUL & INSTALLENGINE CONTROLS - REMOVE/INSTALL/OVERHAULELECTRONIC CONTROL MODULE (ECM)PROGRAMMABLE READ-ONLY MEMORY (PROM)REMOVAL
1990 Chevrolet Chevy Van G20, 4.3 Z, 475/M40
Programmable Read-Only Memory (Prom): Removal
1990 Chevrolet Chevy Van G20, 4.3 Z, 475/M40SECTION Removal
- Remove ECM from vehicle as previously described. Position ECM so that 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 new PROM is to be installed, remove old PROM from PROM carrier.
NOTE:
Note reference notch locations in PROM, carrier and ECM for reassembly reference.
RENDER: 1.0x
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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.