Chevrolet Trax: 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

NOTE: The DTCs listed below set due to a transmission hydraulic/mechanical condition. Perform the Circuit/System Verification and Circuit/System Testing to identify the cause.

DTC P0796

Pressure Control Solenoid Valve 3 Stuck Off - Transmission Hydraulic/Mechanical Performance

DTC P0797

Pressure Control Solenoid Valve 3 Stuck On - Transmission Hydraulic/Mechanical Performance

Circuit/System Description

Pressure control solenoid valve 3 is part of the control solenoid valve assembly, which has no serviceable components. Pressure control solenoid valve 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 speed signals from the automatic transmission input shaft speed sensor and the output shaft speed sensor. 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.
• Engine speed is 400-7,500 RPM for 5 s.
• Transmission output speed is 100 RPM or greater or the throttle position is 0.5% or greater.
• Ignition voltage is 9-32 V.
• Transmission fluid temperature is -6.7ºC (20ºF) or greater.
• High side driver is enabled.
• 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.
• Engine speed is 400-7,500 RPM for 5 s.
• Transmission output speed is 100 RPM or greater or the throttle position is 0.5% or greater.
• Throttle position signal is valid.
• Ignition voltage is 9-32 V.
• Transmission fluid temperature is -6.7ºC (20ºF) or greater.
• High side driver is enabled.
• The throttle position is 10% or greater and the engine torque is 45 N.m (33 lb ft) or greater if attained gear is 1st free wheel.
• DTC runs continuously during shift when the 4-5-6 clutch is commanded OFF, until commanded range is attained.

Conditions for Setting the DTC

P0796

The TCM detects an incorrect gear ratio when the 4-5-6 clutch is commanded ON. This condition must occur 3 times.

P0797

The TCM detects an incorrect gear ratio change when the 4-5-6 clutch is commanded OFF during a shift. This must occur 3 times.

Action Taken When the DTC Sets

• P0796 and P0797 are Type A DTCs.
• TCM commands maximum line pressure.
• TCM freezes transmission adaptive functions.
• TCM inhibits TAP Up/TAP Down functions.
• TCM inhibits manual up, manual down shifts with the shift selector.
• TCM inhibits powertrain braking.
• TCM inhibits neutral idle.
• TCM inhibits auto grade braking.
• TCM limits the transmission to reverse and 3rd gear - DTC P0796 only.
• TCM limits the transmission to reverse and 4th gear - DTC P0797 only.

Conditions for Clearing the DIC/DTC

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

Automatic Transmission Controls Schematics (Encore, MH8 or MHB) , Automatic Transmission Controls Schematics (Trax, MH8 or MHB)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

• Inline Harness Connector End Views (Encore) , Inline Harness Connector End Views (Trax)

Description and Operation

• Drive Range - Fourth Gear (Gen 2/Hybrid)
• Drive Range, Fifth Gear (Gen 2/Hybrid)
• Drive Range, Sixth Gear (Gen 2/Hybrid)
• Electronic Component Description
• Transmission Component and System Description
• 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 (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

WARNING: Refer to Parking Brake and Drive Wheels Warning .

1. Ignition ON.
2. Verify DTC P0716, P0717, P0722, P0723, P077C, P077D, P07BF, or P07C0 was not set by reviewing the scan tool Freeze Frame/Failure Records data.

If any of the DTCs were set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If none of the DTCs were set

3. Engine idling, transmission in Park, with parking brake applied and drive wheels chocked.
4. Verify the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check.

• If the transmission fluid level and condition is not correct

Repair as necessary.

If the transmission fluid level and condition is correct

5. Ignition ON, clear the TCM DTCs with a scan tool.
6. Verify DTC P0796 or P0797 does not set while performing a road test. Refer to Road Test.

If DTC P0796 or P0797 sets

Refer to Circuit/System Testing.

If DTC P0796 or P0797 does not set

7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
8. Verify the DTC does not set.

If the DTC sets

Refer to Circuit/System Testing.

If the DTC does not set

9. All OK.

Circuit/System Testing

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

1. Engine idling at the normal operating temperature.
2. Verify the transmission line pressures are within the specified range. Refer to Line Pressure Check, and Solenoid Valve Pressure (Gen 2) .

If the pressures are not within range

Refer to Fluid Pressure High or Low.

If the pressures are within range

3. Ignition OFF, remove the Q8 Control Solenoid Valve Assembly.
4. Verify the pressure changes for all solenoids when performing the solenoid test. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.

If the pressure does not change

Replace the Q8 Control Solenoid Valve Assembly.

If the pressure changes

5. Verify the mechanical conditions listed below do not exist. Repair or replace as necessary.

P0796 or P0797 - Control Valve Body Assembly

4-5-6 Regulator Valve stuck/sticking - debris, binding, damaged valve, or scored bore.

P0796 - Transmission Cooling/Lubrication

• Restriction/leak in OAC, oil to air, cooler/radiator.
• Restricted/leaking/kinked/damaged transmission oil cooler lines.
• Restriction/leak in transmission fluid pump assembly.

P0796 - Automatic Transmission Fluid Filter Assembly

Oil filter or filter seal loose or damaged.

P0796 - Input Shaft Support

Input shaft tower seals damaged or leaking

P0796 - 4-5-6 Clutch Housing Assembly

4-5-6 Clutch Piston Assembly damaged/leaking.

P0796 - Torque Converter (w/Fluid Pump) Housing Assembly

• Fluid pump housing vanes/rotor/slide damaged/scored.
• Fluid pump or torque converter overstressed due to high temperature.

P0796 - 4-5-6 Reaction Carrier Hub Assembly

4-5-6 Reaction Carrier Hub/Shaft - broken hub weld

P0796 - 3-5-R and 4-5-6 Clutch Housing Assembly

4-5-6 Clutch Backing Plate Retaining Ring not seated/oriented, causing clutch pack/piston overtravel.

P0796 Output Carrier Assembly

Output carrier pinion pins too high or too low.

P0796 or P0797 - Q8 Control Solenoid Valve Assembly

• Clutch Pressure Control Solenoid 3 stuck ON/OFF.
• O-ring seals leaking.
• Valve body filter plate assembly cracked, blocked, or damaged gasket seal.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Perform the Transmission Adaptive Values Learn following all transmission repairs
• Control Module References - for Control Solenoid Valve Assembly replacement, programming and setup

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