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All references to this code (P0753) that I could find point towards a failing ignition switch. Only problem is that most of these references have many more codes associated.

Now this really doesn't apply to our vehicles, but it is one more thing that could potentially be a problem:

Quote:

A wide range of GM vehicles are affected by a condition that may set DTCs P0716, P0717, P0730, P0753, P1860, P1887 or other miscellaneous ransmission DTCs. The condition may be intermittent and may create very harsh shifts. MY 2000-2002 Buick Century, LeSabre, Park Avenue, Regal, Chevy Cavalier, Impala, Malibu, Monte Carlo, Venture, Oldsmobile Alero, Aurora, Intrigue, Silhouette, and Pontiac Bonneville, Grand Am, Grand Prix, Montana and Sunfire along with the 02 Rendevous, 01-02 Lumina, and 01-02 Aztec models with either a 4T65-E, 4T40-E, or 4T45-E transaxle.

The conditions may be caused by a poor or intermittent connection at the 20-pin connector on the transaxle. The wiring harness between the transaxle and the PCM may be stretched or have components forcing it downward. If so; reroute the harness or move the components to relieve tension from the connector. Also check that the connector is fully seated and locked into the transaxle. If no problems are found yet, open the connector. Make sure that the terminals are fully seated in their cavities and that none of the male pins are bent. Also check that the female terminals are not spread and that the crimp connections are secure.

Again, I don't know how much that applies to our trucks, but it is something that can be looked at.

Here's something else for you to look through:
[quote]DTC P0753

Circuit Description

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the OFF/ON/CRANK voltage circuit. The powertrain control module (PCM) controls the solenoid by providing the ground path on the 1-2 SS valve control circuit.

When the PCM detects a continuous open, short to ground or short to power in the 1-2 SS valve circuit, then DTC P0753 sets. DTC P0753 is a type B DTC.

Conditions for Running the DTC

• The system voltage is 10-18 volts.
• The engine speed is greater than 450 RPM for 5 seconds.
• The engine is not in fuel cutoff.

Conditions for Setting the DTC

DTC P0753 sets if one of the following conditions occurs for 5 seconds:

Condition 1

The PCM commands the solenoid ON and the voltage feedback remains high, B+.

Condition 2

The PCM commands the solenoid OFF and the voltage feedback remains low, 0 volts.
Action Taken When the DTC Sets
• The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
• The PCM commands D2 line pressure.
• The PCM inhibits 3-2 downshifts if the vehicle speed is greater than 48 km/h (30 mph).
• The PCM inhibits TCC engagement.
• The PCM inhibits 4th gear in Hot Mode.
• The PCM freezes shift adapts from being updated.
• The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
• The PCM stores DTC P0753 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

• The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and p