FastLearn Procedure: Overview

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

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 so as 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 solenoid A or the pressure control solenoid B
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

IMPORTANT: When performing FastLearn, the following conditions must be met:

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

IMPORTANT: If at any time during the procedure, required conditions are not met, FastLearn may abort and the process will need to be started again from the beginning.

Four steps are required to successfully complete the FastLearn procedure:

PARK Mode
DRIVE Mode
REVERSE Mode
4-5 Clutch Learn Mode