Test Procedure

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.

If a No Forward, No REVERSE, or Will Not Move condition occurs:

Disconnect the C1 connector, GREY, at the transmission control module (TCM).
Set the parking brake.
Apply the service brake.
Start the engine and move the range selector to REVERSE position.

The transmission should engage REVERSE range.

Next, move the range selector to the D4 position. The transmission should engage THIRD range

If REVERSE and THIRD range are available in Limp Home Mode, an electrical failure may be indicated. If only one of the two ranges, or neither, was obtainable, this may indicate an internal hydraulic failure such as:

Failed clutch
Stuck valve
Solenoid failure

The clutches that could possibly have an indicated failure in Limp Home are the 1-2-3-4 clutch, the 3rd, 5th and reverse clutch, and the low and reverse clutch.