FastLearn Procedure: Overview

In general, FastLearn is a procedure for Allison 1000 Series transmissions in which a series of tests are run to allow the transmission control module (TCM) to learn individual clutch characteristics. Once the clutch data is learned, FastLearn translates it to the adaptive data cells, which the TCM uses for clutch control during range shifts. FastLearn is used at GM assembly plants, and allows the vehicle to be driven out of the assembly plant in a near-fully-adapted state to minimize any customer shift concerns. The scan tool version of FastLearn is intended to provide the same benefit following transmission repair or replacement at GM dealerships.

FastLearn must be used when one of the following repairs have been made to the vehicle:

• Transmission replacement or internal service/overhaul
• Valve body repair or replacement, including replacement of the pressure control solenoids
• TCM replacement
• TCM software/calibration update
• Any service in response to a shift quality concern

The scan tool is used to initiate FastLearn by selecting the following commands:

• F3: Special Functions
• F1: Transmission Output Controls
• FastLearn

• Block the drive wheels.
• Apply the parking brake.
• Apply the service brake during DRIVE and REVERSE.
• 0 percent throttle and engine at idle RPM
• Transmission sump temperature is between 40-100°C (104-212°F) - Ref temp bargraph on screen.
• If equipped, 4WD transfer case in 2WD

Three steps are required to successfully complete the FastLearn procedure:

1. PARK Mode
2. DRIVE Mode
3. REVERSE Mode