2004 Chevrolet Optra (CANADA) L4-2.0LFACTORY OEM SERVICE PROCEDURE

Engine Control Module: Service and Repair




Engine Control Module Replacement

Removal Procedure

Factory service manual diagram




Caution: Refer to Battery Disconnect Caution Battery Disconnect Caution.

1. Disconnect the negative battery cable.
2. Remove the air intake tube and resonator.
3. Disconnect the engine control module (ECM) connectors from the ECM.
4. Remove the ECM.

Installation Procedure

Factory service manual diagram



1. Connect the ECM connectors to the ECM.
2. Align the ECM into the mounting base.
3. Snap the ECM into its mounting base.
4. Install the ECM trim locks.
5. Connect the negative battery cable.
6. Perform a crankshaft position (CKP) system variation learning procedure and the idle learn procedure. Refer to Crankshaft Position System Variation Learn Testing and Inspection and Idle Learn Testing and Inspection.

Factory Service Tools

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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.

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