GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Express 🢒 DTC 🢒 DTC P0741, P0751, or P0756

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 P0741 : Torque Converter Clutch (TCC) System - Stuck Off

DTC P0751: 1-2 Shift Solenoid (SS) Valve Performance - No First, Fourth or Fifth Gear

DTC P0756: 2-3 Shift Solenoid (SS) Valve Performance - No First or Second 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

P0741

    • No TCC DTCs P1866, P1867 or P0742.
    • No input speed sensor (ISS) DTCs P0716 or P0717.
    • No output speed sensor (OSS) DTCs P0722 or P0723.
    • Ignition voltage between 8-18 volts.
    • The engine torque is greater than 50 N·m (37 lb ft).
    • The throttle position is 8-90 percent.
    • The transmission fluid temperature is 20-130°C (68-266°F).
    • The gear ratio is within the following ranges:
       - 1.54:1-1.71:1 - 2nd gear
       - 0.95:1-1.05:1 - 3rd gear
       - 0.66:1-0.73:1 - 4th gear
    • The TCC is commanded ON for 0.1 second.
    • The TCC duty cycle is greater than 65 percent.

P0751

    • No ISS DTCs P0716 or P0717.
    • No OSS DTCs P0722 or P0723.
    • No torque converter clutch (TCC) performance DTC P0742, 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 50 N·m (37 lb ft) or greater.

P0756

    • No ISS DTCs P0716 or P0717.
    • No output (shaft) speed sensor (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

P0741

The TCM commands the TCC ON, and the TCC slip is between 150 RPM or greater for 5 seconds, 2 times during the same ignition.

P0751

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

    • The TCM commands 1st gear and the resulting gear ratio is 1.54:1-1.71:1 for 2 seconds.
    • The TCM commands 4th gear and the resulting gear ratio is 0.95:1-1.05:1 for 3 seconds.

P0756

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

    • The TCM commands 1st gear and the resulting gear ratio is 0.66:1-0.73:1 for 2 seconds.
    • The TCM commands 2nd gear and the resulting gear ratio is 0.95:1-1.05:1 for 3 seconds.

Action Taken When the DTC Sets

P0741

    • DTC P0741 is a Type B DTC.
    • The TCM commands elevated line pressure.
    • The TCM commands TCC OFF.
    • The TCM inhibits 4th gear if the transmission is in Hot Mode.
    • The TCM freezes transmission adaptive functions.

P0751

    • DTC P0751 is a Type B DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.

P0756

    • DTC P0756 is a Type A DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • The TCM inhibits 1st gear.

Conditions for Clearing the DTC
    • DTCs P0741 and P0751 are Type B DTCs.
    • DTC P0756 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
    • Inspect transmission fluid lines to radiator. Lines may be pinched, plugged or twisted.
    • Refer to Shift Solenoid Valve State and Gear Ratio .
    • Internal damage to the torque converter may prevent TCC application.

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 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 P0741 was set, operate the vehicle in D at 72 km/h (45 mph) and 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 at 20 percent throttle.
    3. ⇒If the TCC Slip Speed is between 150-250 RPM for greater than 5 seconds, inspect the following components and repair or replace as necessary:
    • TCC PWM solenoid valve mechanically stuck OFF or leaking.
    • TCC regulator apply valve stuck in the OFF position.
    • TCC Sol valve stuck in the OFF position or leaking.
    • TCC enable valve stuck in the OFF position.
    • Misaligned damaged or leaking valve body gasket.
    • Inspect the forward clutch input housing assembly for the input shaft fluid seal ring leaking or worn.
  3. Using the scan tool, clear the DTC. If DTC P0741, P0751 or P0756 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. 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:

P0751

Inspect the shift solenoid/hydraulic circuit for the following conditions.

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

P0756

Inspect the shift solenoid/hydraulic circuit for the following conditions.

    • Debris or chips in the AFL oil passage
    • Debris or chips restricting oil flow in passage #29 of the case or through the spacer plate gasket into the valve body
    • A cracked 2-3 shift solenoid
    • A 2-3 shift valve which is stuck or hung up in the valve body bore
    • A 2-3 shuttle valve which is stuck or hung up in its bore
    • Damaged seals on the shift solenoid valves
    • Refer to Shift Solenoid Leak Test .

Component Testing

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 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.

    • Allow the transmission to operate through all gears and all the TCC to engage. Ensure that the gear ratios match each commanded gear and the TCC slip speed is less than 65 RPM when the TCC is commanded ON.
    •  Shift Solenoid Leak Test