Next thing I would do is look at how the cruise control ( wiring ) circuit ties in with the tork converter clutch . If the code is tripping while you are using cruise control ,and does NOT trip while cruise is not being used , there has to be incorrect values in the converter clutch circuit . The computer (TCM ) in the truck that tells the transmission to shift sees something wrong .
Does the TCM see the converter slipping ? this is the most likely cause .
PO 741 is a terrible code to diagnose over a keyboard .
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
- Transmission internal mechanical problem
The Torque Converter Clutch (TCC) 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.
What would I try next ? a complete transmission fluid replacement with Toyota brand fluid .
This is basicly your next step in the proper diagnosis of PO741 .
Replacing all your fluid will restore friction modifiers to the old fluid .
I would also highly recomend http://www.lubegard.com/~/C-113/LUBE...ATF+Protectant
That lubeguard is available at most transmission shops and it works absolute wonders . I have used it for years .
My 2010 TRD also moves ahead slightly when stopped at a red light . The engine also revs up when this occurs giving you the feeling that you had better push harder on the brakes . My Toyota Matrix does the same thing .Seems to be relative to all Toyota,s I have ever driven .