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According to AllData............


DTC P0785


Circuit Description

The 3-2 shift solenoid (SS) valve assembly is a normally-closed, 3-port, on/off device that controls the 3-2 downshift. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through the ignition 0 voltage circuit. The powertrain control module (PCM) controls the solenoid by providing a ground path on the 3-2 shift solenoid valve control circuit. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The PCM varies the timing between the 3-4 clutch release and the 2-4 band apply, depending on the vehicle speed and the throttle position.


When the PCM detects a continuous open, short to ground or short to voltage in the 3-2 SS valve assembly circuit, then DTC P0785 sets. DTC P0785 is a type B DTC.


DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0785 3-2 Shift Solenoid (SS) Control Circuit


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 P0785 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 a soft landing to third gear.

The PCM commands maximum line pressure.

The PCM inhibits TCC engagement.

The PCM inhibits 4th gear if the transmission is 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 P0785 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 thee diagnostic test runs and passes.

A scan tool can clear the MIL/DTC.

The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.





To sum it up, I think you have a bad 3-2 solenoid. :chevy:

Edited by Fireman31 (see edit history)
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  • 5 weeks later...

i got a question for you i am thinking about getting a procharger for my 5.3. i whould like to to how much of a difference you felt, what numbers it ran if you got it on the dyno, did you install it yourself and was it hard, and where did you buy it and how much? i would appreciate any info thanks

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