P0752

DTC P0742, P0752, or P0757

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis
* Diagnostic Procedure Instructions

DTC Descriptors

* DTC P0742 Torque Converter Clutch (TCC) System - Stuck On
* DTC P0752 1-2 Shift solenoid (SS) Valve Performance - No Second or Third Gear
* DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No Third or Fourth Gear

Diagnostic Fault Information

Diagnostic Fault Information:

Circuit/System Description

The transmission control module (TCM) controls the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is fully applied, the engine is coupled directly to the transmission through the TCC. The TCC used is an electronically controlled capacity clutch (ECCC). The TCM will normally allow a small amount of slip to occur with the ECCC. When the TCC is engaged, TCC slip speed is maintained at approximately 20-50 RPM. The 1-2 shift solenoid (SS) valve and the 2-3 SS valve are supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure. The TCM identifies a 1-2 SS valve or a 2-3 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio.

Conditions for Running the DTC

* No TP sensor DTCs P0121, P0122, or P0123.
* No ISS DTCs P0716 or P0717.
* No OSS DTCs P0722 or P0723.
* No TCC system stuck ON DTC P0742.
* The engine speed is greater than 500 RPM for 5 seconds.
* The transmission fluid temperature is between 20-130°C (68-266°F).

DTC P0742

* No TCC system stuck OFF DTC P0741.
* The calc. throttle position is between 8-90 percent.
* The TCC PWM solenoid valve is commanded OFF.
* The gear ratio is between 0.66:1 and 1.68:1.
* The engine torque is greater than 50 N.m (37 lb ft).
* The vehicle speed is 16 km/h (10 mph) or greater.

DTC P0752

* No TCC system stuck ON DTC P0742.
* No 1-2 SS valve electrical DTCs P0973 or P0974.
* No 2-3 SS valve electrical DTCs P0976 or P0977.
* The calc. throttle position is 8 percent or more.
* The transmission ISS is 150 RPM or more.
* The transmission OSS is 200 RPM or more.
* The engine torque is greater than 50 N.m (37 lb ft).
* The time since the last gear change is 1 second.

DTC P0757

* No TCC system stuck ON DTC P0742.
* No 1-2 SS valve electrical DTCs P0973 or P0974.
* No 2-3 SS valve electrical DTCs P0976 or P0977.
* The calc. throttle position is 8 percent or more.
* The transmission ISS is 150 RPM or more.
* The transmission OSS is 200 RPM or more.
* The engine torque is 40 N.m (29 lb ft) or more when 3rd gear is commanded.
* The time since the last gear change is 1 second.

Conditions for Setting the DTC

DTC P0742

The TCC slip speed is between -20 and 40 RPM for 6 seconds 3 times during the same ignition cycle.

DTC P0752

The following conditions both occur twice in one trip:

Condition 1

The TCM commands 2nd gear and the gear ratio indicates 1st gear, 2.81:1 to 3.11:1 for 2 seconds.

Condition 2

The TCM commands 3rd gear and the gear ratio indicates 4th gear, 0.65:1 to 0.72:1, for 3 seconds.

DTC P0757

The following conditions both occur twice in one trip:

Condition 1

The TCM commands 3rd gear and the gear ratio indicates 2nd gear, 1.54:1 to 1.71:1 for 2 seconds.

Condition 2

The TCM commands 4th gear and the gear ratio indicates 1st gear, 1.54:1 to 3.11:1, for 2 seconds.

Action Taken When the DTC Sets

* DTCs P0742 and P0752 are Type B DTCs.
* DTC P0757 is a Type A DTC.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.

DTC P0742

The TCM commands the TCC ON at maximum capacity.

DTC P0752

The TCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph).

DTC P0757

The TCM inhibits 4th gear.

Conditions for Clearing the DTC

* DTCs P0742 and P0752 are Type B DTCs.
* DTC P0757 is a Type A DTC.

Diagnostic Aids

If the DTC is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist:

* Fluid contamination
* Plugged fluid circuits
* Restricted fluid circuits
* It is possible for an internal TCM failure which may not allow sufficient current to operate the solenoids. Verify TCM functionality by commanding the suspected solenoid ON/OFF using the scan tool and listen for a click.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

* Automatic Transmission Inline 20-Way Connector End View
* Automatic Transmission Internal Connector End Views
* Automatic Transmission Related Connector End Views

Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

* Scan Tool Data List
* Scan Tool Data Definitions
* Scan Tool Output Controls

DTC Type Reference

* Diagnostic Trouble Code (DTC) Type Definitions
* Diagnostic Trouble Code (DTC) List/Type

Circuit/System Verification

Start and idle the engine. Using the scan tool output controls, command the affected solenoid ON and OFF. Observing the CKT Status parameter on the scan tool for the affected solenoid, ensure that the parameter displays OK.

Circuit/System Testing

1. Perform the Transmission Fluid Check. Testing and Inspection
- Correct the transmission fluid level if the fluid is not at the proper level.

2. Using the scan tool, clear the DTC. If DTC P0742 was set, operate the vehicle above 72 km/h (45 mph) with the Calc. Throttle Position between 8 and 90 percent and use the scan tool to command the TCC OFF. Observe the TCC slip speed parameter on the scan tool. The TCC slip speed should be greater than 60 RPM.
- If the TCC Slip Speed is less than 60 RPM, inspect the following components and repair or replace as necessary:

- The TCC control valve stuck in the apply position
- The TCC PWM solenoid valve stuck, exhaust restricted or faulty internal O-ring
- The TCC fluid circuits leaking-refer to Control Valve Body Disassemble in Transmission Unit Repair.
- The TCC blow-off valve or spring for damage or not seating-refer to Case Inspection in Transmission Unit Repair.
- Turbine shaft seals for leaks-refer to Torque Converter Assembly Removal in Transmission Unit Repair.
- Spacer plate gaskets torn or leaking-refer to Control Valve Body Assemble in Transmission Unit Repair.
- Pressure regulator valve stuck-refer to Control Valve Body Disassemble in Transmission Unit Repair.
- Abnormally high or low line pressure-refer to Line Pressure Check. Line Pressure Check Procedure

3. Using the scan tool, clear the DTC. If DTC P0752 or P0757 is set, drive the vehicle and ensure that the TCM commands 1st, 2nd, 3rd, and 4th gears. The ratios should match the commanded gear for all gears. Refer to Shift Solenoid Valve State and Gear Ratio.

- If the gear ratios do not match the commanded gear, inspect the following and repair or replace, as necessary:

DTC P0752

- The 1-2 shift solenoid mechanically stuck ON
- A stuck or binding 1-2 shift valve

DTC P0757

- The 2-3 shift solenoid mechanically stuck ON
- A stuck or binding 2-3 shift valve

Component Testing

1. Perform the Shift Solenoid Leak Test. Shift Solenoid Leak Test
- If the solenoid fails the shift solenoid leak test, replace the affected solenoid.

2. Disconnect the wiring harness connector from the affected solenoid. Measure the resistance for the affected solenoid. The resistance should be between 19-31 ohms for the 1-2 SS and the 2-3 SS. The resistance should be between 10-15 ohms for the TCC PWM solenoid.
- If the resistance is not within the specified range, replace the affected solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair. Verification Tests

* Allow the transmission to operate through all gears. Ensure that the gear ratios match each commanded gear and the TCC slip speed is 150 RPM or greater when the TCC is commanded OFF.
* Shift Solenoid Leak Test
* 1-2 Shift Solenoid Valve Replacement
* 2-3 Shift Solenoid Valve Replacement
* Torque Converter Clutch Pulse Width Modulation Solenoid Replacement
* Control Valve Body Disassemble
* Control Valve Body Cover Removal and Side Cover/Gaskets, Disassemble, Assemble, Install in Transmission Unit Repair Manual