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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 Envoy - 2WD 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P0742, P0752, or P0757

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 Descriptor

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, Fourth or Fifth Gear

Circuit/System Description

The torque converter clutch (TCC) solenoid valve is a normally-open exhaust valve that is used with the torque converter clutch pulse width modulation (TCC PWM) solenoid valve in order to control fluid acting on the converter clutch apply valve. The TCC solenoid valve attaches to the transmission case assembly extending into the pump cover. When grounded, energized, by the transmission control module (TCM), the TCC solenoid valve stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and move the converter clutch apply valve against spring force and into the apply position. In this position, release fluid is open to an exhaust port and converter feed fluid fills the apply fluid circuit. The converter feed fluid applies the TCC. When the TCM no longer provides a ground path, the TCC solenoid valve de-energizes and apply fluid exhausts, releasing the TCC.

Conditions for Running the DTC

P0742

    • No input speed sensor (ISS) DTCs P0716 or P0717.
    • No output speed sensor (OSS) DTCs P0722 or P0723.
    • No TCC performance DTC P0741.
    • No TCC electrical DTCs P2763, P2764.
    • Ignition voltage is between 8-18 volts.
    • The transmission fluid temperature is 20-130°C (50-266°F).
    • The engine speed is 500-6,500 RPM.
    • The engine torque is at least 50 N·m (37 lb ft).
    • The throttle position is 8-90 percent.
    • The commanded gear is not 1st gear and the gear ratio is 0.66:1-1.71:1.
    • The vehicle speed is greater than 16 km/h (10 mph).
    • TCC is commanded OFF.

P0752

    • No ISS DTCs P0716 or P0717.
    • No OSS DTCs P0722 or P0723.
    • No torque converter clutch (TCC) performance DTCs P0742 or P0894.
    • No shift solenoid electrical DTCs P0973, P0974, P0976, or P0977.
    • The engine run time is greater than 5 seconds.
    • The transmission fluid temperature is 20-130°C (68-266°F).
    • The throttle position is 8 percent or greater.
    • The input shaft speed is 150 RPM or greater.
    • The output shaft speed is 150 RPM or greater.
    • The engine torque is at least 50 N·m (37 lb ft).

P0757

    • No ISS DTCs P0716 or P0717.
    • No OSS DTCs P0722 or P0723.
    • No torque converter clutch (TCC) DTC P0742 or P0894
    • No shift solenoid electrical DTCs P0973, P0974, P0976, or P0977.
    • The engine torque is greater than 50 N·m (37 lb ft).
    • The engine run time is greater than 5 seconds.
    • The transmission fluid temperature is 20-130°C (68-266°F).
    • The throttle position is 8 percent or greater.
    • The input shaft speed is 150 RPM or greater.
    • The output shaft speed is 150 RPM or greater.

Conditions for Setting the DTC

P0742

The following conditions occur 3 times in one ignition cycle:

The TCC slip is between -20 to +40 RPM for 6 seconds.

P0752

    • The TCM commands 2nd gear and the resulting gear ratio is 2.91:1-3.21:1 for 2.25 seconds.
    • The TCM commands 3rd gear and the resulting gear ratio is 0.66:1-0.73:1 for 3 seconds.

P0757

Both of the following conditions must occur twice during the same trip:

    • The TCM commands 3rd gear and the resulting gear ratio is 1.54:1-1.71:1 for 2 seconds.
    • The TCM commands 4th, when the engine torque is greater than 10 N·m (7 lb ft) and the resulting gear ratio is 2.91:1-3.21:1 for 2 seconds.

Action Taken When the DTC Sets

P0742

    • DTC P0742 is a Type B DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.

P0752

    • DTC P0752 is a Type B DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • The TCM inhibits 3-2 downshifts if the vehicle speed is greater than 20 km/h (12.4 mph).

P0757

    • DTC P0757 is a Type A DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • 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

The TCC fluid hydraulically applies the TCC, possibly causing an engine stall, under the following conditions:

    • The TCC is hydraulically stuck ON.
    • The parking brake is applied.
    • Any gear range is selected.
    • Contamination may cause the TCC apply valve to intermittently stick in the valve body.
    • Internal damage in the torque converter may cause no TCC apply.
    • Fluid contamination
       - Plugged fluid circuits
       - Restricted fluid circuits
    • Refer to Shift Solenoid Valve State and Gear Ratio .

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General Information

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

Transmission Control Module Scan Tool Information

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 .
    2. ⇒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 in D at 72 km/h (45 mph) with the throttle greater than 15 percent, allowing the transmission to shift through all gears. Use the scan tool to command the TCC ON. Observe the TCC Slip Speed parameter on the scan tool. The TCC Slip Speed should be between -20 to 20 RPM.
    3. ⇒If the TCC Slip Speed is between 130-1,500 RPM for greater than 2.5 seconds, inspect the following components and repair or replace as necessary:
    • Clogged exhaust orifice in the TCC solenoid valve
    • Converter clutch apply valve stuck in the apply position
    • Misaligned or damaged valve body gasket
    • Restricted release passage
    • Restricted transmission cooler line
  3. Using the scan tool, clear the DTC. If DTC P0752 or P0757 is set, drive the vehicle in D and ensure that the TCM commands all gears. The ratios should match the commanded gear for all gears.
⇒If the gear ratios do not match the commanded gear, inspect the following and repair or replace as necessary:

P0752, P0757

    • An internal malfunction
    • Damaged seals on the shift solenoid valve--Refer to Shift Solenoid Leak Test .

Component Testing
  1. Perform the Shift Solenoid Leak Test .
    2. ⇒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 15-20.3 ohms for the 1-2 SS, 2-3 SS and the 4-5 SS. The resistance should be between 10-13.6 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.

    • Allow the transmission to operate through all gears. Ensure that the gear ratios match each commanded gear and the TCC slip speed is 100 RPM or greater with the TCC commanded OFF.
    •  Shift Solenoid Leak Test