P0740-TCC OUT OF RANGE

For a complete wiring diagram Refer to Section 8W

Theory of Operation


When in 2nd, 2nd Prime, 3rd, 4th or 5th 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 LR Solenoid until the torque converter slip difference (difference between engine and transmission input speed) is within 60 rpm. Then the LR 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. TCC-LR 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.


Possible Causes
  
RELATED DTC P0750 PRESENT
  
L/R SOLENOID
  
TCC SWITCH VALVE STUCK
  
TCC REGULATOR VALVE STUCK
  
INPUT SHAFT SEAL RING CUT
  
TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
  

Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)



Diagnostic Test

1.CHECK FOR RELATED DTC P0750



Is the DTC P0750 present also?

Yes
  • Refer to the Transmission category and perform the appropriate symptom.


No
  • Go To 2

2.CHECK IF DTC P0740 IS CURRENT








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






Were there any problems found?

Yes


No
  • Test Complete.

4.CHECK THE LR SOLENOID



Are the DTCs P1775 and P0841 present also?

Yes


No
  • Go To 5

5.CHECK THE TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION








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