Toyota IQ - transmission code

hamz80 (hamz80) 2021-04-26 10:43:46 +0500 #1

Hi Pakwheelers,

I am facing an issue with my Toyota IQ 2009 and its been a while trying to sort this out with various mechanics.
The car runs fine till 70KMPH where the RPM remains under 2000. As soon as the RPM is pushed above that, a jerk and RPM increases to 3000, with almost none or minimum acceleration. The car does not cross 80KMPH regardless how much you push the pedal.
The car gives the code P0741, which is the torque convertor solenoid related code. Abrupt increase in engine speed with hardly any acceleration signals that there is no lockup. Have tried almost everyone and everything, from changing fluid, wiring check, transmission tear down to identify but all in vain. Pertinent to highlight that the car is 221K driven with rings changed in 2019.
Need help on highlighting the real problem and its resolution from seniors. Help from Xulfiqar, Rajaatta or any other senior member will be highly appreciated.

uzeemujeeb (MUZ) 2021-04-26 11:57:20 +0500 #2

is there any maintenance history for vehicle available since your purchase.
transmission CVT oil change etc etc

hamz80 (hamz80) 2021-04-26 12:29:01 +0500 #3

Dear Uzeem,

The car is properly maintained. Changed the CVT oil around 5K KMs ago.
Change interval is 20K since it is in my ownership over the last three years now.

uzeemujeeb (MUZ) 2021-04-26 12:35:03 +0500 #4

the DCT code refers to solenoid malfunction. which city you belong to because rajaatta daniikk are in rwp-isb babarhyd is in haiderabad and there is a auto transmission mechanic by name of usman 03008272720 somewhere in FB area. Syncview 0321 4106898 is in lahore workshop name obama sports truck centre

you may only need a torque converter to resolve the issue not the whole new box

hamz80 (hamz80) 2021-04-26 14:31:56 +0500 #5

I am based in Lahore.
Unfortunately, have already tried Osama for this. Issue wasnt addressed though he tried all possible solutions.
So now looking for some lead for sorting this out.

hamz80 (hamz80) 2021-04-27 10:33:26 +0500 #6

bump.
Any good lead to a reputable CVT transmission guy in Lahore will be highly appreciated.

hamz80 (hamz80) 2021-04-29 13:58:45 +0500 #7

bump

rajaatta (Raja Atta) 2021-04-29 21:18:25 +0500 #8

Try again with usama he is a talented and has a good approach on diagnostics in lahore.

Possible area of trouble can be TCC solenoid,
Wiring loom, or the exu itself so start with the TCC solenoid and its wiring then move slowly toward the ecu replacement.

Most of the cases has to be seem with wiring damage inside the transmission

This k410 is naughty for its convertor solenoid problem. If the problem still persist after the above procedure then be ready to swap the whole transmission.