P0745-TCC STUCK ON.P1811-MAXIUM ADAPT& LONG SHIFT. INTERNAL SERVICE RECCOMMENDED

P1811
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. DTC P1811 is a type C DTC
The 1-2, 2-3 or 3-4 shift is longer than 0.65 seconds, twice in one trip.
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Ask the customer about possible overloading, exceeding the trailer towing limit, or towing in overdrive.

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Ensure that the current PCM calibration is correct for the final drive ratio.

1. Use the scan tool snapshot mode in order to record the shift times.
2. Drive the vehicle in D4 in order to obtain a 1-2, 2-3 and 3-4 upshift.
3. Record the shift times.

Did all the shift times exceed the specified value?
0.65 seconds
Perform the Line Pressure Check Procedure.
Refer to the Line Pressure Check .
Is the line pressure within specifications?
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You may want to take this to the dealer !

p1811 is a transmission code for trans adapt long shift. There is a service bulletin for this code that recommends replacement of the pressure control solenoid in the transmission.

I bought 2003 grnd prix 134000 for $2500.00, other car die cost to fix $3500.00

If all gears are shifting hard, may have a code p1811 set-trans adapt long shift. When this code sets it commands full line pressure causing hard shifts. Usually the pressure control solenoid is at fault. You need to have it scanned for codes.

P0420 catalytic below threshold,Your basically dealing with is a failed catalytic ,
P0742 Torque convertor clutch circuit stuck on or off.
P1811 this is manufacutrer code definition adaptive shift (due to P0742)
P1811 this code is set from towing a trailer in overdrive
when P0742 comes on it usually is accompanied by P1887
If its p1811 then yes it truly is a TCC solenoid being a problem As for catalytic code te catalytic is a mechanical device and yes they do expire from mileage and age

P1811 Maximum Adapt And Long Shift

P0742: Torque Converter Clutch Circuit Stuck On (transmission area)

P1811: Maximum Adapt and Long Shift 2.4L and 3.1L (transmission area)

You need to talk to a transmission specialist.

You need to go and get the car scanned. IT may have a code p1811 max adapt long shift. If it does replace the filter and fluid and the pressure control solenoid

You need to get someone to do a code-read with a transmission capable scanner (transmission shop) You probably have a bad EPC (electronic pressure control) causing the transmission to slip, therefore setting a p1811 code (max adapt/long shift) which will max out the line pressure making your shifts very firm (but stopping the slipping/delayed shifts...this is a fail safe mode designed to keep your transmission from slipping until you address the underlying cause)

There are diagnostic tools that could help detect what your problem is. The Snap-On Modis, or preferably a "Tech-2" GM scanner. Any reputable transmission shop, or GM dealer should have at least one of the two. It sounds to me like it could be the transmissions "EPC" (Electronic Pressure Control solenoid) The EPC controls main line pressure, in an effort to keep shift firmness, and shift duration at one specific level. This is to compinsate for the natural wear a transmission encounters, and to keep emissions as low as possable, by keeping shift duration low. When the EPC malfunctions (and thats somthing that they like to do in the 4t65E), it typically starts to shift harder than normal. They typically throw a P1811 code. (P1811 is a "max adapt-long shift" code) And the malfunction can be intermittent. Hope this helps, and good luck.
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