P0740-TCC OUT OF RANGE

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

When in 2nd, 3rd, or 4th gear, the Torque Converter Clutch (TCC) can be locked or partially locked when certain conditions are met. The TCC piston is electronically modulated by increasing the duty cycle of the LR/TCC solenoid until the torque converter slip difference (difference between engine and turbine speed) is within 60 rpm. Then the LR/TCC solenoid is fully energized (FEMCC / 100% duty cycle). Torque converter slip is monitored in FEMCC to ensure adequate clutch capacity. The transmission will attempt normal EMCC operation (not in limp-in) even after the MIL is illuminated. MIL will illuminate after 5 minutes of accumulated slip in FEMCC.

When Monitored:
The Torque Converter Clutch (TCC) is in FEMCC or PEMCC, Transmission temperature is hot, Engine temperature is greater than 38 degrees C or 100 degrees F, Transmission Input Speed greater than engine speed, TPS less than 30 degrees , and brake not applied.
Set Condition:
The TCC is modulated by controlling the duty cycle of the L/R Solenoid until the difference between the Engine rpm and the Transmission Input Speed rpm or duty cycle is within a desired range. The DTC is set after the period of 10 seconds and 3 occurrences of either: FEMCC - with slip greater than 100 rpm or PEMCC - duty cycle greater than 85%.

Possible Causes

INTERNAL TRANSMISSION

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

Diagnostic Test

1. CHECK IF RELATED DTCS ARE PRESENT

With the scan tool, read Transmission DTCs.

Are the DTCs P0750 and/or P0841 present also?

Yes

Refer to the Transmission category and perform the appropriate symptom.

Go To 2

2. CHECK IF THE DTC IS CURRENT

Ignition on, engine not running.
With the scan tool, record and erase DTCs.
Drive the vehicle until it is fully warmed up to at least 43 degrees C (110 degrees F).
Perform the following step 3 times.
Drive the vehicle at 80 km/h (50 mph) and allow 4th gear to engage for at least 10 seconds. Close the throttle, then tip back in until the throttle angle is between 25 and 29 degrees. Note that if you go over 30 degrees, you must back off of the throttle and retry.

Did the TCC engage during any of the attempts?

Yes

Go To 3

Perform the Hydraulic Pressure test per the Service Information and repair the internal transmission components and Torque convertor as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

3. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wiring and connectors while checking for shorted and open circuits.
This DTC can also be set under extreme temperature conditions. This is usually caused by an internal problem. Verify if the problem is only experienced under extreme hot or cold conditions.
With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.
Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

Were there any problems found?

Yes

Repair as necessary.

Perform 42RLE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

Test Complete.