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 MANUALSCHEVROLET1991SUBURBAN 1/2 TON 2WD V8-350 5.7LREPAIR AND DIAGNOSISRELAYS AND MODULESRELAYS AND MODULES - POWERTRAIN MANAGEMENTRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSENGINE CONTROL MODULESERVICE AND REPAIRENGINE CONTROL MODULE (ECM) REPLACEMENT
1991 Chevrolet Suburban 1/2 Ton 2WD V8-350 5.7L
Engine Control Module (ECM) Replacement
1991 Chevrolet Suburban 1/2 Ton 2WD V8-350 5.7LSECTION Engine Control Module (ECM) Replacement
When replacing a production ECM with a service ECM, transfer the broadcast code and production number from the production unit to the service unit. Also, during replacement, the PROM, and if equipped, the CALPAK must be removed from the ECM being replaced and transferred to the new unit. Refer to "PROM, REPLACE" and "CALPAK, REPLACE" for procedure.
1. Disconnect battery ground cable.
2. Remove right side kick panel, then disconnect two ECM electrical connectors.
3. Remove ECM mounting hardware.
4. Remove ECM from passenger compartment.
5. Reverse procedure to install.
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.