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DTC P0796 or P0797

DTC P0796 or P0797

Diagnostic Instructions


• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• 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. Pressure control solenoid valve 3 regulates the transmission fluid pressure (TFP) to the R1/4-5-6 clutch regulator valve that controls the pressure to the low and reverse clutch and the 4-5-6 clutch. The transmission control module (TCM) calculates gear ratio based on the RPM signals from the 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 ignition voltage is 8.6 volts or greater.

• The engine speed is 400 RPM or greater for 5.0 seconds.

• The output speed is 16 RPM or greater, or the throttle position is 0.5 percent or greater.

• The throttle position signal is valid.

• The high side driver is enabled.

• The transmission fluid temperature (TFT) is -7°C (19°F) or greater.



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 8.6 volts or greater.

• The engine speed is 400 RPM or greater for 5.0 seconds.

• The output speed is 16 RPM or greater, or the throttle position is 0.5 percent or greater.

• The throttle position signal is valid.

• The high side driver is enabled.

• The TFT is -7°C (19°F) or greater.

• The engine torque is 20 Nm (15 lb ft) or higher when 1st gear is commanded.


Conditions for Setting the DTC

P0796

The TCM has detected an incorrect gear ratio or neutral condition when the low and reverse or 4-5-6 clutch is commanded ON. This condition must occur 3 times.

P0797

The TCM has detected an incorrect gear ratio change when the low and reverse clutch or the 4-5-6 clutch is commanded OFF during a shift or when 4th ratio is detected in 1st gear. This condition must occur 3 times.

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/Down function.

• The TCM inhibits manual shifting of forward gears.

• The TCM limits the transmission to Reverse, 1st, and 3rd gear operation.



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/Down function.

• The TCM inhibits manual shifting of forward gears.

• The TCM limits the transmission to Reverse and 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 display, monitor, and verify multiple transmission data parameters at one time, after the road test.

Reference Information

Connector End View Reference


• Component Connector End Views

• Inline Harness Connector End Views


Description and Operation

Transmission General Description

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1.
Note

If other DTCs are set, diagnose those DTCs first.


Engine idling in Park, with parking brake applied and drive wheels chocked.

2. 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 .

3. 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 .

4. Engine idling in Park, verify with a scan tool the Transmission ISS/OSS Supply Voltage parameter displays OK.

5. 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.

6. 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.

7.
Note

Perform a scan tool snapshot, during the road test.


Perform the road test . Verify the transmission operation performs as indicated, in the road test instructions.

8. 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

9. After you complete the steps described above, check the diagnostic trouble code is not reset by driving the vehicle according to the conditions for running diagnostic trouble codes (DTC). You can also drive the vehicle according to the conditions you see in Freeze Frame/ Failure records. If the vehicle passes the circuit/system verification procedure, then stop. Do not perform the circuit/system test or component test as this may result in unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections .


Circuit/System Testing


1. Perform the line pressure check . Check that the transmission's line pressure gauge is within the range specified in the table Line PC-solenoid valve pressure. Refer to Solenoid Valve Pressure .

2. If not within the specified ranges, refer to Fluid Pressure High or Low .

3. Remove control solenoid valve assembly Q8 with ignition OFF. See Replacing control solenoid valve assembly and transmission control module .

4. Perform the Test of the control solenoid valve assembly and the transmission control module's solenoid performance . A pressure change should occur for each solenoid.

5. If the Q8 control solenoid valve assembly does not pass the performance test, replace the Q8 control solenoid valve assembly.

6. Listed in the table below, are conditions for each component that could set DTC P0796 or P0797. Carefully inspect each component for that condition. Repair or replace as necessary.


DTCs Component Condition
P0796 P0797 Control Valve Upper Body Assembly (349) 4-5-6 regulator valve (326) stuck/sticking - debris, binding, damaged valve, or scored bore
P0796 Lower Control Valve Body Assembly (374)
• Actuator feed limit circuit supply fluid to solenoid restricted or not available - debris, stuck limit valve (362) or sediment blockage

• 4-5-6 clutch boost valve (360) - binding or scored bore - can cause harsh shifts

• 4-5-6 clutch accumulator piston (366) - leaking, cracked, or broken


P0796 P0797 Input shaft support 3-5-R and 4-5-6 clutch fluid seal rings (404) damaged, worn, or leaking
P0796 P0797 Q8 Control Solenoid Valve Assembly (314)
• Clutch pressure control solenoid 3 stuck On or stuck Off

• Control solenoid filter plate assembly cracked, blocked, or damaged gasket seal


P0796 4-5-6 Clutch Housing Assembly (441)
• 4-5-6 clutch piston assembly (439) damaged/leaking

• Inner/outer seal damaged

• Dam pressure too high


P0796 A/Trans Case Cover (403) Blow off regulator ball stuck
P0796 Transmission Cooling/Lubrication
• Restriction/leak in oil to air (OAC) cooler/radiator

• Restricted/leaking/kinked/damaged transmission oil cooler lines

• Restriction/leak in transmission fluid pump assembly


P0796 Torque Converter Assembly (27) Fluid pump or torque converter overstressed due to high temperature, fluid boiled out
P0796 4-5-6 Reaction Carrier Hub Assembly 4-5-6 reaction carrier hub/shaft - broken hub weld
P0796 A/Trans Fluid Filter Assembly (201) Oil filter (201) or filter seal (202) loose or damaged
P0796 A/Trans Fluid Pump (203) A/Trans pump fluid outlet seal assembly (57) damaged/leaking


Repair Instructions

Note
• Perform the Resetting of the transmission's adaption after all transmission repairs.

• Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .


Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Control Valve Lower Body and Upper Body Replacement

• Low and Reverse Clutch and 1-2-3-4 Clutch Plate Removal and 3-5-Reverse and 4-5-6 Clutch Housing Disassemble

• Control Module References for control solenoid valve assembly replacement, setup, and programming