68RFE Automatic Transmission

P0740-TCC OUT OF RANGE

For a complete wiring diagram Refer to Diagrams/Electrical

Theory of Operation


When in 2nd through 6th gear, the torque converter clutch (TCC) can be engaged when certain conditions are met. The 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. 68RFE - Pre-Diagnostic Troubleshooting Procedure


Diagnostic Test


1. CHECK FOR RELATED DTC P0750
With the scan tool, read DTCs.
Is the DTC P0750 present also?

Yes


- Repair the DTC(s).


No


- Go to 2



2. CHECK IF THE DTC IS CURRENT
With the scan tool, read and RECORD ALL Transmission DTCs. After recording DTCs, erase DTCs.
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.
Perform the following steps 3 times.
Using the AutoStick(R) (ERS) to place the transmission in 2nd gear.
While monitoring the Engine Speed and Input Speed, accelerate smoothly at light to moderate throttle from 1200 rpm to 2500 rpm and watch for TCC engagement.
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
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.
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.
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 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test


No


- Test Complete.



4. CHECK THE L/R-TCC SOLENOID
With the scan tool, check for other transmission DTCs.
Are the DTCs P1775 and P0841 present also?

Yes


- Replace Transmission Solenoid/TRS Assembly.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test


No


- Go to 5



5. CHECK THE TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
Repair internal transmission as necessary.
Check for the following possible causes.
Inspect the Transmission Oil Pump and Valve Body.
Check the Torque Converter Switch Valve and the Torque Converter Clutch Control Valve (located in the pump valve body) for sticking in the bore.
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.
If no problems are found, replace the Transmission Solenoid/TRS Assembly.
View repair

Repair


- In all cases, replace the Torque Converter. Make sure to check all other possible causes in addition to the Torque Converter.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test