Allison LCT1000 Overdrive Disable Lamp Inoperative after Installation of IP - kw automatic disable fifth indicator IPC switch

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

The Overdrive Disable lamp may be inoperative after the installation a new instrument panel (IPC) however, the function will still be operative. The Overdrive Disable function prevents the Allison LCT1000 transmission from obtaining 5th gear.

The IPC must be programmed using a Tech 2 Scan Tool and TIS2000 to make the IPC fully functional with the vehicle. The replacement IPC may appear to be functional as the speedometer and gauges will work only certain vehicle specific options will not work without programming the IPC.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(03-05 Chevrolet Silverado) and (03-05 GMC Sierra)

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