C 3500 Truck 2WD V8-6.6L DSL Turbo VIN 1 (2002)
Engine Control Module: Service and Repair
Powertrain Control Module (PCM) Replacement
Service of the engine control module (ECM) should normally consist of either replacement of the ECM or electrically erasable programmable read only
memory (EEPROM) programming. If the diagnostic procedures call for the ECM to be replaced, the ECM should be inspected first to see if the correct
part is being used. If the correct part is being used, remove the faulty ECM and install the new service ECM.
IMPORTANT:
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To prevent internal ECM damage, the ignition must be OFF when disconnecting or reconnecting power to the ECM. For example, when working
with a battery cable, ECM pigtail, ECM fuse, or jumper cables.
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Remove any debris from the ECM connector surfaces before servicing the ECM. Inspect the ECM module connector gaskets when diagnosing or
replacing the ECM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the ECM.
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The replacement ECM will not be programmed. DTC P0601 and P0602 indicate the EEPROM is not programmed or has malfunctioned. The
following MUST be performed anytime the ECM is replaced:
1. Programming of the EEPROM.
2. The ECM Password Learn procedure-Refer to Engine Control Module (ECM) Programming Procedure (On-Board) or Engine Control Module
(ECM) Programming Procedure (Off-Board).
3. Resetting the engine oil life monitor-Refer to GM Oil Life System - Resetting in Maintenance and Lubrication.
4. The Functional Check.
The Functional Check must be performed anytime the ECM is disconnected, loses power, or is reprogrammed.
Removal Procedure
1. Disconnect the negative battery cable from the battery and move aside.
2. Release the ECM cover mounting holes (1,5) away from the mounting tabs on the ECM mounting bracket.
3. Release the ECM cover (8) from the mounting bracket.
4. Remove the ECM cover.
NOTE: Do not touch the connector pins or soldered components on the circuit board in order to prevent possible electrostatic discharge (ESD)
damage to the PCM.
5. Disconnect the ECM harness connectors (6).
6. Release the spring latch (2) from the ECM.
7. Release the ECM mounting tabs (3) from the ECM.
8. Remove the ECM (4) from the engine compartment.
