GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2009 🢒 Ascender - 2WD 🢒 DTC 🢒 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

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

DTC P0742: Torque Converter Clutch (TCC) System - Stuck On

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 input speed sensor (ISS) DTCs P0716 or P0717.
    • No output speed sensor (OSS) DTCs P0722 or P0723.
    • No TCC DTCs P0742.
    • No TCC PWM DTCs P2763 or P2764.
    • 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.

P0742

    • No ISS DTCs P0716 or P0717.
    • No OSS DTCs P0722 or P0723.
    • No TCC DTC P0741.
    • No TCC PWM DTCs P2763 or P2764.
    • Ignition voltage between 8-18 volts.
    • The transmission fluid temperature is 20-130°C (68-266°F).
    • The engine speed is 500-6500 RPM.
    • The engine torque is at least 80 N·m (59 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.

Conditions for Setting the DTC

P0741

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

P0742

The TCM commands TCC ON, and the TCC slip is between -20 RPM and 30 RPM for 6 seconds, 3 times during the same ignition.

Action Taken When the DTC Sets

P0741

    • DTC P0741 is a Type B DTC.
    • The TCM commands maximum 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.

P0742

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

Conditions for Clearing the DTC

DTCs P0741 and P0742 are Type B DTCs.

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 Verification

Ensure that the transmission fluid level is at the proper level by performing the Transmission Fluid Check.

Circuit/System Testing
  1. Operate the vehicle at 72 km/h (45 mph) with the throttle position at 20 percent. Command TCC ON with a scan tool while observing the scan tool TCC Slip Speed parameter.
    2. ⇒If the TCC Slip Speed is 150 RPM for 5 seconds, inspect the following conditions and repair/replace as necessary:
    • TCC PWM solenoid valve for a damaged exhaust orifice.
    • 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.
    • TCC for being mechanically stuck OFF.
    • Inspect the forward clutch input housing assembly for the input shaft fluid seal ring leaking or worn.
    • Refer to Symptoms - Automatic Transmission NO TCC apply.
    ⇒If the TCC Slip Speed is between -20 and 40 RPM for greater than 5 seconds, inspect for the following conditions and repair/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.
  2. 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.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.