P0740
P0740-TCC OUT OF RANGE
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
When in 2nd, through 5th gear, the torque converter clutch (TCC) can be engaged when certain conditions are met. The L/R-TCC piston is electronically modulated by increasing the duty cycle of the L/R-TCC Solenoid until the torque converter slip difference (difference between engine and transmission input speed) is within 60 rpm. Then the L/R-TCC solenoid is fully energized (FEMCC - 100% duty cycle). Torque converter slip is monitored in FEMCC to ensure adequate clutch capacity.
- When Monitored:
During Electronically Modulated Converter Clutch (EMCC) Operation.
- Set Condition:
Transmission must be in EMCC, with input speed greater than 1750 rpm. L/R-TCC Solenoid achieves the maximum duty cycle and can not pull engine speed within 60 rpm of input speed. Also when the transmission is in FEMCC and the engine slips TCC more than 100 rpm for 10 seconds. This DTC can take up to five minutes of problem identification before illuminating the MIL.
Always perform the Pre-Diagnostic Troubleshooting Procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. CHECK FOR RELATED DTC P0750
1. With the scan tool, read transmission DTCs.
Is the DTC P0750 present also?
Yes
- Testing and InspectionPerform the appropriate diagnostic procedure.
No
- Go To 2
2. CHECK IF DTC P0740 IS CURRENT
1. With the scan tool, Read and RECORD ALL Transmission DTCs. After recording DTCs, erase DTCs.
2. Drive the vehicle until the transmission temperature is at least 43° C or 110° F and the engine temperature at least 49° C or 120° F.
3. Perform the following steps 3 times.
4. Drive the vehicle to the speed of at least 88 Kmh or 55 mph.
5. Allow 4th or 5th gear to engage for at least 10 seconds.
6. Close the throttle.
7. Tip back into the throttle until the TPS angle is between 25 and 29 degrees.
NOTE: If the throttle angle goes over 30 degrees, you must close the throttle and try again.
Did the TCC engage during any of the attempts, Engine speed approximately equal to input speed?
Yes
- Go To 3
No
- Go To 4
3. CHECK WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wires while checking for shorts and open circuits.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorts and open circuits.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test
No
- Test Complete.
4. CHECK THE L/R-TCC SOLENOID
1. With the scan tool, check for other transmission DTCs.
Are the DTCs P1775 and P0841 present also?
Yes
- Replace Transmission Solenoid/TRS Assembly. Transmission Solenoid and TRS Assembly - Removal.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test
No
- Go To 5
5. CHECK THE TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
1. Repair internal transmission as necessary.
2. Check for the following possible causes.
3. Inspect the Transmission Oil Pump Assembly.
4. Check the Torque Converter Switch Valve and the Torque Converter Clutch Control Valve for sticking in the bore.
5. Check the Teflon seal rings on the input shaft.
NOTE: If one of the seal rings is cut, the loose piece will often lodge in the TCC switch valve, causing it to stick in its bore.
6. If no problems are found, replace the Transmission Solenoid/TRS Assembly. Transmission Solenoid and TRS Assembly - Removal.
Repair
- In all cases, replace the Torque Converter. Make sure to check all other possible causes in addition to the Torque Converter. Torque Converter - Removal.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test