For 1990-2009 cars

### 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

### Diagnostic Fault Information

Hydraulic Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
1-2 SS Valve | -- | -- | -- | P0751, P0752
2-3 SS Valve | -- | -- | -- | P0756, P0757
TCC PWM Valve | -- | -- | -- | P0741, P0742

### Typical Scan Tool Data

#### Torque Converter Clutch (TCC) System Parameter Data

Circuit | Normal | Short to Ground | Open/High Resistance | Short to Voltage
--- | --- | --- | --- | ---
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: OK
1-2 Sol. CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts
2-3 Sol. CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts
TCC Duty Cycle CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts

### 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.

### Conditions for Running the DTC

#### P0741

• | 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.

• | No TCC release switch DTCs P0842 or P0843.

• | No TCC control circuit DTCs P2763 or P2764.

• | The calc. throttle position is between 8-90 percent.

• | The TCC PWM solenoid valve is commanded ON.

• | The TCC duty cycle is 65 percent or greater for 2 seconds.

• | The commanded gear is 1st.

• | The engine speed is greater than 500 RPM for 5 seconds.

• | The transmission fluid temperature is between 20-130°C (68-266°F).

• | The engine torque is greater than 50 N·m (37 lb ft).

#### P0742

• | No TP sensor DTCs P0121, P0122, or P0123.

• | No ISS DTCs P0716 or P0717.

• | No OSS DTCs P0722 or P0723.

• | No TCC system stuck OFF DTC P0741.

• | No TCC control circuit DTCs P2763 or P2764.

• | The calc. throttle position is between 8-90 percent.

• | The TCC PWM solenoid valve is commanded OFF.

• | The gear ratio is between 0.63:1 and 1.73:1.

• | The engine torque is greater than 50 N·m (37 lb ft).

• | The vehicle speed is 16 km/h (10 mph) or greater.

• | The engine speed is greater than 500 RPM for 5 seconds.

• | The transmission fluid temperature is between 20-130°C (68-266°F).

### Conditions for Setting the DTC

#### P0741

The TCC slip speed is 150 RPM or greater for 8 seconds 2 times during the same ignition cycle.

#### P0742

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

### Action Taken When the DTC Sets

#### P0741

• | DTC P0741 is a Type B DTC.

• | The TCM forces the TCC OFF.

• | The TCM inhibits TCC engagement.

• | 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 forces the TCC ON.

• | The TCM commands the TCC ON at maximum capacity.

• | The TCM commands maximum line pressure.

• | 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.

• | Internal damage to the torque converter may prevent TCC application.

• | 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

Component Connector End Views

#### 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

Control Module References for scan tool information

### Circuit/System Verification

1. Perform the Transmission Fluid Check to verify correct fluid level and condition. The transmission fluid level should be within the crosshatch band and the transmission fluid should be red or dark brown.

⇒ | If the transmission fluid is low or discolored, refer to Automatic Transmission Fluid Filter and Seal Replacement .

2. Operate the vehicle at 72 km/h (45 mph) with the throttle position at 20 percent. Command the TCC ON with a scan tool while observing the scan tool TCC Slip Speed parameter. The reading should be below 175 RPM.

⇒ | If the TCC Slip Speed is greater than 175 RPM for greater than 5 seconds, inspect for the following conditions and repair/replace as necessary:

• | TCC PWM solenoid valve mechanically stuck OFF 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

⇒ | If the TCC Slip Speed is between 150-1,500 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

3. 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.

• | 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