Torque converter clutch hang up

This code is set when the transmission control module detects improper voltage at the torque converter clutch. This can be caused by low tranny fluid/dirty tranny fluid/defective torque converter clutch solenoid/electrical connections to from solenoid

there should be a torque converter clutch servo/solenoid and it is controlled by a sensor
run the fault codes first

Replace the Torque Converter Switch

Your trans is working like a standard shift,
when you forget to put the clutch in at a stop

P0743 - Torque Converter Clutch Circuit Electrical
Symptoms - Engine Light ON (or Service Engine Soon Warning Light) Possible causes - Faulty torque converter clutch solenoid valve
- Torque converter clutch solenoid valve harness or connectors
- Torque converter clutch solenoid valve circuit is open or shorted
- Low transmission fluid level
- Dirty transmission fluid
Tech notes This is an electrical problem code. Could be a problem to the harness to the TCC solenoid, the TCC solenoid connector or the TCC solenoid it self.

P0740 JEEP - Torque Converter Clutch Circuit
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Transmission shift shock
- Vehicle may not shift into the highest gear

Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Faulty torque converter clutch solenoid valve
- Torque converter clutch solenoid valve harness or connectors
- Torque converter clutch solenoid valve circuit is open or shorted

When is the code detected?
Torque Converter Clutch (TCC) unlocked for 10 sec., ECM commands converter lock-up and did not record engine speed drop.

P0740 JEEP Description
The torque converter clutch solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

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SOUND LIKE FAULTY TRANSMISSION TORQUE CONVERTER CLUTCH SOLENOID.WHAT HAPPENING WHEN YOU COME TO A STOP.WHEN YOUR FOOT PRESS THE BRAKE PEDAL THE TRANSMISSION TORQUE CLUTCH SOLENOID SUPPOSE TO UNLOCK TORQUE CONVERTER TO KEEP FROM STALLING THE ENGINE IF NOT THATS WHAT CAUSING THE ENGINE TO STALL OUT.SO HAVE THE BRAKE LIGHT SWITCH CHECK OUT AND HAVE THE TRANSMISSION SCANNED FOR A TRANSMISSION TORQUE CONVERTER CLUTCH SOLENOID FAULT.

the torque converter clutch solenoid is kind of like the clutch in a manual transmission. automatic transmissions inherently have a little slip in the transfer of power between the engine and transmission, since the transfer of power is done with fluid instead of a mechanical clutch. however, when the car is in overdrive and cruising, the TCC solenoid acts like a clutch and locks up the torque converter, making a mechanical connection and eliminating the slippage. when you accelerate or downshift, it turns off. if this switch hangs up, when you come to a stop, the car will bog down just like a manual trans would if you don't push in the clutch pedal

you nee to get your torque converter lockup solenoid replaced. If you are not very mechanically inclined you probably don't want to attempt this yourself

sounds like the torque converter is not disengaging you might need a TCC switch (torque converter clutch)

If the converter clutch does not lock at all it may be a problem with the ECM, or some problem with the emissions or sensors have the ECM "out of loop". (in which case the "Check Engine" appears) If the converter clutch is hanging engaged, killing the engine at stops, that is more likely a problem with a solenoid valve in the transaxle. You will need to consult a manual covering the transaxle for the location of the solenoid.