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
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Hydraulic Performance
|
1-2 SS Valve Control
| P0973
| P0973
| P0974
| P0751, P0752
|
2-3 SS Valve Control
| P0976
| P0976
| P0977
| P0756, P0757
|
TCC PWM Valve Control
| P2764
| P2764
| P2763
| P0741, P0742
|
Typical Scan Tool Data
Circuit Status
Circuit
| Normal
| Short to Ground
| Open/High Resistance
| Short to Voltage
|
Operating Conditions:
Engine running, normal operating temperature
Parameter Normal Range:
Indeterminate
|
1-2 Sol. CKT Status
| Indeterminate
| Short to GND
| Open
| Short to Volts
|
2-3 Sol. CKT Status
| Indeterminate
| Short to GND
| Open
| Short to Volts
|
TCC Duty Cycle CKT Status
| Indeterminate
| Short to GND
| Open
| 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 normally allows 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. 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
• | No TP sensor DTC P0120 or P0220. |
• | No ISS DTC P0716 or P0717. |
• | No OSS DTC P0722 or P0723. |
• | No TCC system stuck ON DTC P0742. |
• | The engine speed is greater than 500 RPM for 5 seconds. |
• | The transmission fluid temperature (TFT) is between 20-130°C (68-266°F). |
• | The engine torque is greater than 50 N·m (37 lb ft). |
• | No TCC release switch DTC P0842 or P0843. |
• | 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 5 seconds. |
• | The commanded gear is 2nd, 3rd, or 4th. |
P0751
• | No TP sensor DTC P0120 or P0220. |
• | No ISS DTC P0716 or P0717. |
• | No OSS DTC P0722 or P0723. |
• | No TCC system stuck ON DTC P0742. |
• | The engine speed is greater than 500 RPM for 5 seconds. |
• | The TFT is between 20-130°C (68-266°F). |
• | The engine torque is greater than 50 N·m (37 lb ft). |
• | No 1-2 SS valve electrical DTC P0973 or P0974. |
• | No 2-3 SS valve electrical DTC P0976 or P0977. |
• | The calc. throttle position is 8 percent or greater. |
• | The transmission ISS is 150 RPM or greater. |
• | The transmission OSS is 160 RPM or greater. |
• | The time since the last gear change is 1.5 seconds. |
P0756
• | No TP sensor DTC P0120 or P0220. |
• | No ISS DTC P0716 or P0717. |
• | No OSS DTC P0722 or P0723. |
• | No TCC system stuck ON DTC P0742. |
• | The engine speed is greater than 500 RPM for 5 seconds. |
• | The TFT is between 20-130°C (68-266°F). |
• | The engine torque is greater than 50 N·m (37 lb ft). |
• | No 1-2 SS valve electrical DTC P0973 or P0974. |
• | No 2-3 SS valve electrical DTC P0976 or P0977. |
• | The calc. throttle position is 8 percent or greater. |
• | The transmission ISS is 150 RPM or greater. |
• | The time since the last gear change is 1.5 seconds. |
Conditions for Setting the DTC
P0741
The TCC slip speed is 175 RPM or greater for 5 seconds, 6 times during the same ignition cycle.
P0751
The following conditions both occur twice in 1 trip:
Condition 1
The TCM commands 1st gear and the gear ratio indicated 2nd gear, 1.48:1-1.65:1. for 2 seconds.
Condition 2
The TCM commands 4th gear and the gear ratio indicates 3rd gear, 0.95:1-1.05:1, for 3 seconds.
P0756
The following conditions both occur twice in 1 trip:
Condition 1
The TCM commands 1st gear with the transmission OSS 160 RPM or greater, the TCC slip speed is -20 RPM or greater, and the gear ratio indicates 4th gear, 0.65:1-1.87:1, for 3 seconds.
Condition 2
The TCM commands 2nd gear and the gear ratio indicates 3rd gear, 0.95:1-1.05:1, for 3 seconds.
Action Taken When the DTC Sets
• | DTCs P0741 and P0751 are type B DTCs. |
• | DTC P0756 is a type A DTC. |
• | The TCM freezes transmission adaptive functions. |
P0741
• | The TCM forces the TCC OFF. |
• | The TCM inhibits TCC engagement. |
• | The TCM inhibits 4th gear if the transmission is in Hot Mode. |
P0751
The TCM commands maximum line pressure.
P0756
• | The TCM commands maximum line pressure. |
• | The TCM inhibits 1st gear. |
Conditions for Clearing the DTC
• | DTC P0741 and P0751 are type B DTCs. |
• | DTC P0756 is a type A DTC. |
Diagnostic Aids
If the DTC is cleared, then will not set again when the vehicle is driven, some of the following conditions may exist:
• | Restricted fluid circuits |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Testing
- Perform the
Transmission Fluid Check
.
⇒ | Correct the transmission fluid level if the fluid is not at the proper level. |
- Using the scan tool, clear the DTC. If DTC P0741 was set, operate the vehicle greater than 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 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 |
• | The TCC blowoff valve or spring for damage or not seating |
• | The TCC signal orifice in the spacer plate plugged |
• | The #1 check ball missing or leaking |
• | The spacer plate gaskets torn or leaking |
• | The turbine shaft seals for leaks |
• | The torque converter clutch |
- Using the scan tool, clear the DTC. If DTC P0751 or P0756 is set, drive the vehicle to ensure 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
- Perform the
Shift Solenoid Leak Test
.
⇒ | If the solenoid fails the shift solenoid leak test, replace the affected solenoid. |
- Disconnect the wiring harness connector from the affected solenoid. Measure the resistance for the affected solenoid. The resistance should be between 19 and 31 ohms for the 1-2 SS and the 2-3 SS. The resistance
should be between 10 and 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 diagnostic procedure.