Diagnostic Instructions

DTC Descriptors

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

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

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

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

Scan Tool 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 to 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

P0741

P0751

P0756

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.

P0751

The following conditions both occur twice in one trip:

Condition 1

The TCM commands 1st 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 3rd gear, 0.95:1 to 1.05:1, for 4 seconds.

P0756

The following conditions both occur twice in one trip:

Condition 1

The TCM commands 1st gear with the transmission OSS 200 RPM or more, the TCC slip speed is -20 RPM or more, and the gear ratio indicates 4th gear, 0.65:1 to 1.87:1, for 2 seconds.

Condition 2

The TCM commands 2nd gear and the gear ratio indicates 3rd gear, 0.95:1 to 1.05:1, for 3 seconds.

Action Taken When the DTC Sets

DTC P0741

DTC P0751

The TCM commands maximum line pressure.

DTC P0756

Conditions for Clearing the DTC

Diagnostic Aids

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

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

DTC Type Reference

Circuit/System Testing

1. Perform the Transmission Fluid Check .

⇒	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 above 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 below 175 RPM.

⇒	If the TCC Slip Speed is greater than 175 RPM, inspect the following components and repair or replace as necessary:

•	The cooling system for plugging--the cooling lines may be pinched. Refer to Transmission Fluid Cooler Flushing and Flow Test .

•	The TCC control valve for sticking

•	The TCC regulator valve for sticking

•	The pressure regulator valve

•	The TCC PWM solenoid valve stuck and O-ring seal for leaks--refer to Control Valve Body Disassemble .

•	The TCC blowoff valve or spring for damage or not seating--refer to Case Inspection .

•	The TCC signal orifice in the spacer plate plugged

•	The #1 check ball missing or leaking

•	The spacer plate gaskets torn or leaking--refer to Control Valve Body Assemble .

•	The turbine shaft seals for leaks--refer to Torque Converter Assembly Removal .

•	The torque converter clutch--refer to Torque Converter Diagnosis .

3. Using the scan tool, clear the DTC. If DTC P0751 or P0756 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:

P0751

•	The 1-2 shift solenoid mechanically stuck OFF

•	A stuck or binding 1-2 shift valve

•	Damaged seals on the shift solenoid valve

P0756

•	The 2-3 shift solenoid mechanically stuck OFF

•	A stuck or binding 2-3 shift valve

•	Damaged seals on the shift solenoid valve

Component Testing

1. Perform the 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.