Thanks for the question.
I don't feel you will need to have the transmission rebuilt.
Here is the code description:
The transmission pressure is modified by an adaptive modifier which controls the shift execution time. This diagnostic tests the time required to accomplish the shift. If the shift takes longer than 0.65 seconds and the adaptive modifier cannot shorten this time, then a counter increases by one.
If the PCM detects a counter value of 2 during one trip, then DTC P1811 sets.
This will most likely be caused by the transmission pressure control solenoid. In order to properly test for this is to do a line pressure check while using a scan tool that can turn the solenoid on and increase the ampreage of the solenoid. This will cause the pressures to vary and determine if the solenoid is the failed part.
I would suggest getting a second opinion from another shop.
Let me know if you have any questions.
I typed in a 6.00 bonus for you but, apparently, it didn't go through.
That is ok, I appreciate the accept.
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