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Home >> Buick >> 2010 >> Allure AWD (CANADA) V6-3.0L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0796 >> 6T30/6T40/6T45 - Automatic Transmission

6T30/6T40/6T45 - Automatic Transmission




DTC P0796 or P0797

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptors
DTC P0796
- Clutch Pressure Control Solenoid 3 - Stuck Off

DTC P0797
- Clutch Pressure Control Solenoid 3 - Stuck On

Circuit/System Description

The clutch pressure control (PC) solenoid 3 is part of the control solenoid valve assembly which has no serviceable components. PC solenoid 3 regulates transmission fluid pressure to the reverse/4-5-6 regulator valve which controls pressure to the reverse/4-5-6 clutch. The transmission control module (TCM) calculates gear ratio based on the RPM signals from the automatic transmission input speed sensor (ISS) and the output speed sensor (OSS). The TCM compares the expected transmission gear ratio to the calculated gear ratio for each commanded gear.

Conditions for Running the DTC

P0796
* DTC P0101, P0102, P0103, P0106, P0107, P0108, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or P182E is not set.
* The engine speed is greater than 500 RPM for 5 seconds.
* The transmission output speed is 650 RPM or greater or the throttle position is 0.5 percent or greater.
* The ignition voltage is 9.0 volts or greater.
* The transmission fluid temperature is 0°C (32°F) or greater.
* The high side driver (HSD) is enabled.
* The throttle position signal is valid.

P0797
* DTC P0101, P0102, P0103, P0106, P0107, P0108, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or P182E is not set.
* The ignition voltage is 9.0 volts or greater.
* The transmission fluid temperature is 0°C (32°F) or greater.
* The HSD is enabled.
* The transmission output shaft speed is 200 RPM or greater.

Conditions for Setting the DTC

P0796

The TCM detects an incorrect on-coming clutch gear ratio (incorrect gear ratio), or flare.

P0797

The TCM detects an incorrect off-going clutch gear ratio (incorrect gear ratio), or shift tie-up.

Action Taken When the DTC Sets

P0796
* DTC P0796 is a Type A DTC.
* The TCM commands maximum line pressure.
* The TCM inhibits torque converter clutch (TCC).
* The TCM freezes transmission adaptive functions.
* The TCM inhibits TAP Up/TAP Down functions.
* The TCM inhibits manual up, manual down shifts with the shift selector.
* The TCM limits the transmission to 3rd gear operation.

P0797
* DTC P0797 is a Type A DTC.
* The TCM commands maximum line pressure.
* The TCM inhibits TCC.
* The TCM freezes transmission adaptive functions.
* The TCM inhibits TAP Up/TAP Down functions.
* The TCM inhibits manual up, manual down shifts with the shift selector.
* The TCM limits the transmission to 4th gear operation.

Conditions for Clearing the DIC/DTC

DTCs P0796 and P0797 are Type A DTCs.

Diagnostic Aids

Before performing a road test, configure and setup the scan tool for snapshot mode. This allows you to monitor, display, and verify multiple transmission data parameters at one time, after the road test.

Reference Information
Schematic Reference

* Drive Range - Fourth Gear (Fourth Gear)
* Drive Range, Fifth Gear (Fifth Gear)
* Drive Range, Sixth Gear (Sixth Gear)

Description and Operation

* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Warning

Apply the parking brake and block the drive wheels before performing this procedure in order to prevent bodily injury.

Note: If other DTCs are set, diagnose those DTCs first.

1. Engine idling in Park, with parking brake applied and drive wheels chocked.
2. Perform the Transmission Fluid Level and Condition Check (Transmission Fluid Level and Condition Check) to verify correct fluid level and condition.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning (Control Solenoid Valve and Transmission Control Module Assembly Cleaning), to dislodge debris and free up the valves.
4. Monitor the Transmission Fluid Pressure (TFP) switch 5 with a scan tool. Place the gear select lever in Park, Reverse, and Neutral range. Verify the TFP switch 5 parameter states are correct for Park, Reverse, and Neutral. Refer to Transmission Fluid Pressure Switch Logic (Transmission Fluid Pressure Switch Logic).
5. Place the gear select lever in Drive range. Command the shift transmission with a scan tool through all forward ranges. Verify the TFP switch 5 parameter states are correct for all forward ranges. Refer to Transmission Fluid Pressure Switch Logic (Transmission Fluid Pressure Switch Logic).
6. Engine idling in Park, verify with a scan tool the Transmission ISS/OSS Supply Voltage test status parameter displays OK.
7. Engine idling in Park. Observe the Transmission ISS parameter on the scan tool, while varying the engine speed. The Transmission ISS parameter should vary with engine speed and not drop out.
8. Operate the vehicle at 16-32 km/h (10-20 mph) while observing the Transmission OSS parameter on the scan tool. The Transmission OSS parameter should vary with the vehicle speed and not drop out.

Note: Perform a scan tool snapshot, during the road test.

9. Perform the Road Test (6T30/6T40/6T45 - Automatic Transmission). Verify the transmission operation performs as indicated in the road test instructions.
10. Review the scan tool snapshot data. Verify the following transmission data parameters display the correct values for each gear range.

* Transmission ISS
* Transmission OSS
* PC Solenoid 3
* Transmission Fluid Pressure Switch 5

11. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Note: You must perform the Circuit/System Verification first.

1. Perform the Line Pressure Check (Line Pressure Check). Verify the transmission line pressures are within the range specified in the Line PC Solenoid Valve Pressure table. Refer to Solenoid Valve Pressure (Solenoid Valve Pressure).

• If not within the specified range, refer to Fluid Pressure High or Low (Fluid Pressure High or Low).

2. Ignition OFF, remove the control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement (6T30/6T40/6T45 - Automatic Transmission).
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test).

• If the control solenoid valve body does not pass the performance test, replace the control solenoid valve assembly.

4. Inspect for the following conditions and repair/replace as necessary.





Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Important: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).


* Refer to Control Module References (Programming and Relearning) for control solenoid valve assembly replacement, setup, and programming.
* Perform the Transmission Adaptive Values Learn (6T30/6T40/6T45 - Automatic Transmission) following all transmission related repairs.
* Perform the:

- Internal Components Removal (8. Internal Components Removal)
- 3-5-Reverse and 4-5-6 Clutch Housing Disassemble (21. 3-5-Reverse and 4-5-6 Clutch Housing Disassemble)
- 3-5-Reverse and 4-5-6 Clutch Housing Assemble (22. 3-5-Reverse and 4-5-6 Clutch Housing Assemble)
- 3-5-Reverse and 4-5-6 Clutch Housing, and Input, Reaction, and Output Carrier Installation (24. 3-5-Reverse and 4-5-6 Clutch Housing, and Input, Reaction, and Output Carrier Installation)

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