P0797
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
- Pressure Control Solenoid Valve 3 Stuck Off
DTC P0797
- Pressure Control Solenoid Valve 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 R1/4-5-6 regulator valve which controls pressure to the reverse and low clutch and the 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 400 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 (TFT) is -7°C (19°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 engine speed is greater than 400 RPM for 5 seconds.
* The transmission output speed is 650 RPM or greater or the throttle position is 0.5 percent or greater.
* The throttle position signal is valid.
* The ignition voltage is 9.0 volts or greater.
* The TFT is -7°C (19°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 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 reverse and 3rd gear.
P0797
* DTC P0797 is a Type A DTC.
* The TCM commands maximum line pressure.
* 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 reverse and 4th gear.
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 (Gen 1) Drive Range - Fourth Gear (Gen 1)Drive Range - Fourth Gear (Gen 2/Hybrid)
* Drive Range, Fifth Gear (Gen 1) Drive Range, Fifth Gear (Gen 1)Drive Range, Fifth Gear (Gen 2/Hybrid)
* Drive Range, Sixth Gear (Gen 1) Drive Range, Sixth Gear (Gen 1)Drive Range, Sixth Gear (Gen 2/Hybrid)
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 Control Module References 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 Testing and Inspection to verify correct fluid level and condition.
3. Monitor the Transmission Fluid Pressure Switch 5 parameter with a scan tool. Place the gear select lever in Park, Reverse, and Neutral range. Verify the Transmission Fluid Pressure Switch 5 parameter states are correct for Park, Reverse, and Neutral. Refer to Transmission Fluid Pressure Switch Logic Transmission Fluid Pressure Switch Logic.
4. Place the gear select lever in Drive range. Command the shift transmission with a scan tool through all forward ranges. Verify the Transmission Fluid Pressure Switch 5 parameter states are correct for all forward ranges. Refer to Transmission Fluid Pressure Switch Logic Transmission Fluid Pressure Switch Logic.
5. Engine idling in Park, verify with a scan tool the Transmission ISS/OSS Supply Voltage test status parameter displays OK.
6. 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.
7. 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.
8. Perform the Road Test Initial Inspection and Diagnostic Overview. Verify the transmission operation performs as indicated in the road test instructions.
9. Review the scan tool snapshot data. Verify the following transmission data parameters display the correct values for each gear range.
* Transmission ISS
* Transmission OSS
* Pressure Control Solenoid Valve 3 Pressure Command
* Transmission Fluid Pressure Switch 5
10. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
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 (Gen 1) Solenoid Valve Pressure (Gen 1)Solenoid Valve Pressure (Gen 2) Solenoid Valve Pressure (Gen 2).
• If not within the specified range, refer to Fluid Pressure High or Low Fluid Pressure High or Low.
2. Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement Service and Repair.
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 Q8 control solenoid valve body does not pass the performance test, replace the Q8 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.
Note: 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 Control Module References for control solenoid valve assembly replacement, setup, and programming.
* Perform the Transmission Adaptive Values Learn Programming and Relearning following all transmission related repairs.
* Perform the:
- Internal Components Removal 8. Internal Components Removal
- 3-5-Reverse and 4-5-6 Clutch Housing Disassemble (6T40/45/50 - Gen 1) 24. 3-5-Reverse and 4-5-6 Clutch Housing Disassemble (6T40/45/50 - Gen 1)3-5-Reverse and 4-5-6 Clutch Housing Disassemble (6T40/45/50 - Gen 2) 25. 3-5-Reverse and 4-5-6 Clutch Housing Disassemble (6T40/45/50 - Gen 2)
- 3-5-Reverse and 4-5-6 Clutch Housing Assemble (6T40/45/50 - Gen 1) 26. 3-5-Reverse and 4-5-6 Clutch Housing Assemble (6T40/45/50 - Gen 1)3-5-Reverse and 4-5-6 Clutch Housing Assemble (6T40/45/50 - Gen 2) 27. 3-5-Reverse and 4-5-6 Clutch Housing Assemble (6T40/45/50 - Gen 2)
- 3-5-Reverse and 4-5-6 Clutch Housing, and Input, Reaction, and Output Carrier Installation 30. 3-5-Reverse and 4-5-6 Clutch Housing, and Input, Reaction, and Output Carrier Installation