Chevrolet Trax: DTC P0961-P0963

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 P0961

Line Pressure Control Solenoid Valve Performance

DTC P0962

Line Pressure Control Solenoid Valve Control Circuit Low Voltage

DTC P0963

Line Pressure Control Solenoid Valve Control Circuit High Voltage

Circuit/System Description

The line pressure control solenoid valve is part of the control solenoid valve assembly which has no serviceable components. The normally high line pressure control solenoid valve regulates and directs oil pressure to the pressure regulator valve. Increasing line pressure control solenoid valve pressure increases transmission line pressure. The transmission control module (TCM) varies the current to the line pressure control solenoid valve by controlling the amount of time the low side driver is ON and OFF. Decreasing the ON time, decreases the current to the line pressure control solenoid, which increases line pressure control solenoid oil pressure by closing OFF the solenoid exhaust port. Increasing the current to the line pressure control solenoid decreases line pressure control oil pressure by opening the solenoid exhaust port. Line pressure control solenoid power is supplied by the TCM through a high side driver. The high side driver protects the circuit and components from excessive current flow. If excessive current flow is detected, the high side driver will turn OFF. When the fault is corrected, the high side driver will reset.

Conditions for Running the DTC

• Engine speed is 400-7,500 RPM for 5 s.
• Ignition voltage is 9-32 V.
• Runs continuously when above conditions are met.

Conditions for Setting the DTC

P0961

TCM detects an internal electrical malfunction of the line pressure control solenoid valve circuit where the measured line pressure control solenoid valve current does not equal the commanded line pressure control solenoid valve current for 5 s.

P0962

TCM detects a short to ground on the line pressure control solenoid valve control circuit for 2 s.

P0963

TCM detects an open circuit or short to voltage on the line pressure control solenoid valve control circuit for 5 s.

Action Taken When the DTC Sets

P0961 or P0963

• P0961 and P0963 are Type B DTCs.
• TCM freezes transmission adaptive functions.
• TCM commands maximum line pressure.

P0962

• P0962 is a Type A DTC.
• TCM limits the transmission to 4th gear and reverse.
• TCM inhibits the torque converter clutch (TCC).
• TCM commands maximum line pressure.
• TCM freezes transmission adaptive functions.
• TCM turns the high side driver OFF.
• TCM inhibits neutral idle.
• TCM inhibits Tap Up/Down function.
• TCM inhibits manual shifting of forward gears.
• TCM enables torque management.

Conditions for Clearing the DTC

• P0961 and P0963 are Type B DTCs.
• P0962 is a Type A DTC.

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

• 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

Special Tools

DT-48616-10 Adapter Harness

For equivalent regional tools, refer to Special Tools .

Circuit/System Verification

WARNING: Refer to Parking Brake and Drive Wheels Warning .

1. Engine idling, transmission in Park, with service brake applied. Move the S3 Transmission Shift Lever into each gear position for 2-3 s and back into the Park position.
2. Verify the scan tool parameters listed below do not display Malfunction:

• Line Pressure Control Solenoid Valve Performance Test Status
• Line Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status
• Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status

If Malfunction is displayed

Refer to Circuit/System Testing.

If Malfunction is not displayed

3. 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.
4. Verify the DTC does not set.

If the DTC sets

Refer to Circuit/System Testing.

If the DTC does not set

5. All OK.

Circuit/System Testing

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

1. Ignition OFF, remove the Q8 Control Solenoid Valve Assembly.
2. Verify the Q8 Control Solenoid Valve Assembly is not contaminated with any debris and clean as necessary. Refer to Control Solenoid Valve and Transmission Control Module Assembly Inspection.

If contaminated

Repair as necessary.

If not contaminated

3. Verify the resistance is within the specified range for each solenoid valve listed in the Control Solenoid Valve and Transmission Control Module Assembly Inspection.

If the resistance is not within range

Replace the Q8 Control Solenoid Valve Assembly.

If the resistance is within range

4. Place the Q8 Control Solenoid Valve Assembly on a clean work surface near the transmission assembly.
5. Connect the DT-48616-10 adapter harness between the vehicle harness connector and the Q8 Control Solenoid Valve Assembly connector. Ignition ON.
6. Verify the scan tool parameters listed below do not display Malfunction:

• Line Pressure Control Solenoid Valve Performance Test Status
• Line Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status
• Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status

If Malfunction is displayed

Replace the Q8 Control Solenoid Valve Assembly.

If Malfunction is not displayed

7. All OK.

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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