Chevrolet Trax: DTC P0741 OR P0742

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 P0741

Torque Converter Clutch (TCC) System Stuck Off - Transmission Hydraulic/Mechanical Performance

DTC P0742

Torque Converter Clutch (TCC) System Stuck On - Transmission Hydraulic/Mechanical Performance

Circuit/System Description

The torque converter clutch (TCC) pressure control solenoid valve is part of the control solenoid valve assembly which has no serviceable components. The TCC pressure control solenoid valve is normally low and regulates transmission fluid pressure to the TCC regulator valve in the lower valve body and the TCC control valve in the fluid pump assembly. When vehicle operating conditions are appropriate to apply the torque converter clutch, the transmission control module (TCM) will increase TCC pressure control solenoid valve current flow, thereby increasing pressure to move the TCC control valve into the apply position. When the TCC is fully applied, the engine is coupled directly to the transmission. TCC release is accomplished by the TCM decreasing current flow to the TCC pressure control solenoid valves, which decreases the apply pressure and allows the TCC control valve to move to the release position. The TCM calculates torque converter slip speed based on the speed signal from the input shaft speed sensor and engine RPM provided by the engine control module (ECM).

Conditions for Running the DTC

P0741

• 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, P0741, P0742, P2763, or P2764 is not set.
• Engine speed is 400-7,500 RPM or greater for 5 s.
• Ignition voltage is 9-32 V.
• Transmission fluid temperature is between -6.7 to +130ºC (+20 to +266ºF).
• Throttle position is 8% or greater.
• Engine torque is 50 N.m (36 lb ft) or greater.
• Engine torque signal is valid.
• Throttle position signal is valid.
• TCM detects the transmission gear ratios listed below for the commanded gear when TCC is commanded ON:

• 2nd gear ratio is between 2.75-3.17.
• 3rd gear ratio is between 1.78-2.04.
• 4th gear ratio is between 1.35-1.55.
• 5th gear ratio is between 0.93-1.07.
• 6th gear ratio is between 0.70-0.80.

• DTC runs continuously when the above conditions are met.

P0742

• 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, P0741, P0742, P2763, or P2764 is not set.
• Engine speed is 400-7,500 RPM for 5 s.
• Ignition voltage is 9-32 V.
• Transmission fluid temperature is between 15-130ºC (59-266ºF).
• Calculated throttle position was 10% or greater and has not dropped below 2%.
• Engine torque signal is valid.
• Throttle position signal is valid.
• Engine torque is 60 N.m (44 lb ft) or greater.
• Vehicle speed greater than 1 km/h (0.6 mph).
• TCC is commanded OFF.
• Engine torque signal is valid.
• Throttle position signal is valid.
• DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0741

• TCC pressure command is 500 kPa (73 PSI) or greater for 2 s.
• TCM detects TCC slip is 130 RPM or greater for 5 s.
• The above conditions must occur 2 times.

P0742

TCM detects the TCC slip is between -50 and +13 RPM for 1 s when TCC is commanded OFF. This condition must occur 8 times.

Action Taken When the DTC Sets

P0741

• P0741 is a Type B DTC.
• TCM inhibits 6th gear.
• TCM initiates Hot Mode shift pattern.
• TCM commands the TCC OFF.
• P0742
• P0742 is a Type A DTC.
• TCM initiates Hot Mode shift pattern.
• TCM freezes transmission adaptive functions.
• TCM commands the TCC ON.
• TCM inhibits neutral idle.

Conditions for Clearing the DIC/DTC

• P0741 is a Type B DTC.
• P0742 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 Solenoid Assembly Test Kit & Adapter Harness

For equivalent regional tools, refer to Special Tools .

Circuit/System Verification

1. Ignition ON, engine OFF.
2. Verify DTC P0716, P0717, P07BF, or P07C0 was not set by reviewing the scan tool TCM Failure Records.

If any of the DTCs were set

Refer to DTC P0716, P0717, P07BF, or P07C0.

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 P0741 or P0742 does not set while performing a road test. Refer to Road Test.

If DTC P0741 or P0742 sets

Refer to Circuit/System Testing.

If DTC P0741 or P0742 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 pressure changes

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

P0741 Upper Valve Body

Release exhaust port/orifice plugged or blocked.

P0741 or P0742 - Upper Valve Body

Torque converter clutch regulator valve stuck/sticking - debris, binding, damaged valve, or scored bore.

P0741 - Channel Plate and Spacer Plate

Oil channels or orifices blocked by debris.

P0741 or P0742 - Fluid Pump Assembly

Torque converter clutch control valve stuck/sticking - debris, binding, damaged valve, or scored bore.

P0741 - Torque Converter

• Torque converter clutch delamination or material worn off.
• Converter bolts too long damaging the clutch apply surface.
• Damaged seal

P0741 - Support

Damaged seal.

P0741 or P0742 - A/Trans Case Cover (403)

• Pressure release blow-off not seating/sealing.
• Damaged spring.

P0741 - Turbine Shaft O-ring Seal

Cut or damaged.

P0741 or P0742 - Q8 Control Solenoid Valve Assembly

• Torque converter clutch pressure control solenoid stuck OFF or leaking.
• Torque converter clutch pressure control solenoid stuck ON.
• Control signal fluid supply leak due to valve body filter plate assembly cracked, 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 Valve Body Assembly Removal
• Control Module References for Control Solenoid Valve Assembly replacement, programming and setup.

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