complete exhaust system from front to back including cat, resonator and muffler. This also started overnight, ran great and the next morning ran like crap.

 

I have a basic code reader...no codes. I had the battery disconnected today checking the resistance of the shift modules they all check out within spec. I'll have to drive the car around a bit to get the computer reset and I'll bring it to my friends shop to put a real scanner on it. After checking the resistance of the modules I did pull them out and checked them manually, they all clicked closed when energized. Although not the best way to check them, I put a rubber hose on each and blew though once energized, checking that hey were closing. One, although hard to tell may have had a slight leak (the line pressure mod) so for 45 bucks, I replaced it. I today read on another thread that you may have to drive the car a hundred miles or so to allow the computer to recalibrate itself. So, I'll drive it gingerly for awhile and see what happens. Any other ideas would be appreciated. Thanks.

 

To assist you there is a sticky on this transmission.
Learn-in procedure, pinouts, sensor id, etc.
https://www.saturnforum.com/forum/sa...mp6-mp7-11537/

 

So here's the latest update. The car is back to normal. Originally I changed the crank sensor because it was clearly out when I checked the resistance. This made a positive improvement for about a month. then, It must have been just a coincidence that the issue started again right when I changed the radiator. So, for good measure changed the output sensor as well, as it was at the bottom limit of acceptable resistance. They were quite inexpensive so it was worth the risk. It didn't make a difference, all well. Next I checked the modules for resistance and they all were in spec. (I checked them by probing the leads coming out of the top of the transmission cover.) This is a valueless beater car so I thought I would just have some fun and try to figure it out on my own. So I pulled off the trans cover and pulled each of the modules to make sure they were actually closing when activated. They all "clicked" and worked fine. Then I checked to see if they were sealing when activated and I found one that leaked under pressure. (The one toward the front of the car. Line pressure module.) Simple and cheap enough so I changed it and it didn't make much of a difference but it did change some. Then I read that the computer has to relearn the shift pattern and timing associated with the new parts. I then drove the car gingerly for several days and each day it ran better and better and now it's back to normal. So that's it, for under $100 bucks I fixed the car myself and learned a little along the way.

 

Thank you for returning with the update.

So what do you believe the actual problem was?

 

Sounds like it might have been the line pressure module, but there's no way to ever really be 100% sure since you changed so many different things. Could have been one or a combination. The main thing is that you hung in there with it and fixed it. So, kudos to you and your tenacity.

 

I only changed 3 parts,1st the output sensor which made a difference for about a month. Then the crank sensor which was at the bottom end of acceptable resistance but that didn't make a difference. lastly was checking the line pressure module which did click and close but not properly seal when energized. I would therefor say it was the line pressure module at fault. I should add that I did have a mechanic check the ecm with a professional scanner and it showed no codes, Can't explain that either.

 

Glad it is up and running!

 

I'm adding this in the hopes that someone might find it useful.

Learn-In Procedure
Like many other electronically controlled transmissions the TAAT is adaptive to various transaxle conditions. Ideally the adaptive parameters should be reset using the service stall system (SSS). This of course should only be done after the following have occurred:

• The transaxle has been replaced.
• The line pressure actuator has been replaced.
• New clutch plates have been installed (trans overhaul).
• Valvebody has been replaced.
• The PCM has been replaced.

Of course for most of us, using the SSS to reset those values is not possible but regardless the vehicle will still need to be driven and a learn-in procedure followed for the quickest improvement in drivability. If the official learn-in procedure can't be done for whatever reason the transmission will still eventually learn and adapt to the new conditions. It will just take longer and act strange in the mean time.

1. If there is a shift mode switch - place it in normal mode.
2. Warm up the transmission (oil temp. above 45deg C (113deg F)).
3. Perform 10 sets of upshift (1-2, 2-3, 3-4) at 30% throttle:

• For DOHC (LLO) Engine (SL2, SW2, SC2 and SC after 199?)

1. While coasting at 56 km/h (35 mph) slowly
   accelerate to half throttle to achieve a 4-3
   downshift.
2. With selector in D3 while coasting at 32 km/h (20 mph)
   slowly accelerate to 75% throttle to
   achieve 3-2 downshift.
   
   Repeat both procedures five times.

• For SOHC (L24) Engine (SL, SW, SC before 199?)

1. While coasting at 64 km/h (40 mph) slowly
   accelerate to half throttle to achieve a 4-3
   downshift.
2. With selector in D3 while coasting at 48 km/h (30 mph) slowly
   accelerate to one half throttle to achieve a 3-2 downshift.
   
   Repeat both procedures five times.

 

This too.