Engine Control Module Replacement

WARNING: This page is about a different car, the 2021 GMC Sierra 3500 HD and 2021 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

Courtesy of GENERAL MOTORS COMPANY

Callout	Component Name
Preliminary Procedures Before removing the engine control module (ECM), perform SPS function Prepare Control Module for Removal, if available. NOTE: The Prepare Control Module for Removal function can only be performed when communication with the old control module is still possible. Before removing engine control module (ECM), record oil life percentage remaining and Fuel Injector flow identifier codes. Disconnect the negative battery cable. Battery Negative Cable Disconnection and Connection (Duel Battery)Battery Negative Cable Disconnection and Connection (Single Battery) Front Wheelhouse Liner Replacement
1	Engine Control Module Bracket Bolt [4x] CAUTION: Refer to Fastener Caution . Tighten 2.5N.m (22 lb in)
2	Engine Control Module WARNING: Refer to Safety Glasses Warning . CAUTION: Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components. CAUTION: Turn the ignition OFF when installing or removing the control module connectors and disconnecting or reconnecting the power to the control module (battery cable, powertrain control module (PCM)/engine control module (ECM)/transaxle control module (TCM) pigtail, control module fuse, jumper cables, etc.) in order to prevent internal control module damage. Control module damage may result when the metal case contacts battery voltage. DO NOT contact the control module metal case with battery voltage when servicing a control module, using battery booster cables, or when charging the vehicle battery. In order to prevent any possible electrostatic discharge damage to the control module, do no touch the connector pins or the soldered components on the circuit board. Remove any debris from around the control module connector surfaces before servicing the control module. Inspect the control module connector gaskets when diagnosing or replacing the control module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the control module. The replacement control module must be programmed. NOTE: Before removing the engine control module (ECM), record the oil life percentage remaining. Use the scan tool to reset the Engine Oil Life remaining back to the original percentage recorded. Procedure Disconnect the electrical connectors from the engine control module. If replacing the engine control module, it is necessary to reprogram the replacement module. Control Module References

Callout

Component Name

Preliminary Procedures

Before removing the engine control module (ECM), perform SPS function Prepare Control Module for Removal, if available.
NOTE:
The Prepare Control Module for Removal function can only be performed when communication with the old control module is still possible.
Before removing engine control module (ECM), record oil life percentage remaining and Fuel Injector flow identifier codes.
Disconnect the negative battery cable. Battery Negative Cable Disconnection and Connection (Duel Battery)Battery Negative Cable Disconnection and Connection (Single Battery)
Front Wheelhouse Liner Replacement

Engine Control Module Bracket Bolt [4x]

CAUTION:

Refer to Fastener Caution .

Tighten
2.5N.m (22 lb in)

Engine Control Module

WARNING:

Refer to Safety Glasses Warning .

CAUTION:

Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components.

CAUTION:

Turn the ignition OFF when installing or removing the control module connectors and disconnecting or reconnecting the power to the control module (battery cable, powertrain control module (PCM)/engine control module (ECM)/transaxle control module (TCM) pigtail, control module fuse, jumper cables, etc.) in order to prevent internal control module damage.
Control module damage may result when the metal case contacts battery voltage. DO NOT contact the control module metal case with battery voltage when servicing a control module, using battery booster cables, or when charging the vehicle battery.
In order to prevent any possible electrostatic discharge damage to the control module, do no touch the connector pins or the soldered components on the circuit board.
Remove any debris from around the control module connector surfaces before servicing the control module. Inspect the control module connector gaskets when diagnosing or replacing the control module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the control module.
The replacement control module must be programmed.

NOTE:

Before removing the engine control module (ECM), record the oil life percentage remaining. Use the scan tool to reset the Engine Oil Life remaining back to the original percentage recorded.

Procedure

Disconnect the electrical connectors from the engine control module.
If replacing the engine control module, it is necessary to reprogram the replacement module. Control Module References