Backup Park Lock Actuator Disarming (with MHG): Introduction

WARNING: This page is about a different car, the 2020 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.

The Backup Park Lock function is an electrically isolated smart actuator inside the Transmission Range Control Module that is activated when the transmission does not achieve Park. When the Backup Park Lock function is activated, the gear is "disarmed" which rotates the torsional spring forcing the transmission manual shaft to the Park position. The procedure below is designed to disarm the Backup Park Lock Actuator when the rod linkage is adjusted (if equipped) or if the Transmission Range Control Module is being removed then reinstalled. Before you start, read these procedures carefully and completely. For further information regarding the Transmission Range Selector system refer to Electronic Transmission Range Selector Description .

Before Running the Disarming Procedure

Ensure Transmission Range Control Module and Engine Control Module software packages are the most current software available.
Resolve any current DTC's that are present relating to the Electronic Transmission Range Selector system prior to running the disarming procedure. Refer to Electronic Transmission Range Selector Description . Faults in any component or module that work together in this system may cause a disarming procedure failure.
Ensure the MDI tool is equipped with the latest software and is securely connected to the data link connector. If there is an interruption during disarming, disarming failure or ECU damage may occur.
Stable battery voltage is critical during programming. Any fluctuation, spiking, over voltage or loss of voltage will interrupt programming. When required, install a battery maintainer or power supply that provides a steady and stable voltage. Do not use a battery charger, as charging voltage will often fluctuate when connected to the vehicle. This may interrupt programing. If a battery maintainer is not available, connect a fully charged 12 V jumper or booster pack disconnected from the AC voltage supply.
Turn OFF or disable systems that may put a load on the vehicles battery such as; interior lights, exterior lights (including daytime running lights), HVAC, radio, etc.

Starting the Disarming Procedure

With your foot off the brake, press and hold the Start/Run Button for 10 seconds to set the ignition correctly.
Install a scan tool.
Verify that the transmission fluid temperature is 50°F (10°C) or greater before running the disarming procedure.
In the scan tool under Transmission Range Control Module, Configuration / Reset Functions perform the Backup Park Lock Actuator Disarming procedure. Follow all on-screen instructions.
If disarming procedure failure occurs, refer to wiring diagnostics to resolve any electrical faults.
Attempt rerunning the disarming procedure 2 additional times before replacing Transmission Range Control Module. If the test successfully completed, cycle the ignition OFF.