Electrical / Limp Mode.

[TheAdvocate]

Ive done a lot of research on limp mode. Im going to check the codes that I get from it tomorrow, but here are some things we have done to get it to work and yet to see it fail again...

First I charged the battery to get it working.
2nd, drained some tranny fluid because there was to much in there...
3rd, flushed tranny fluid and refilled.
4th, Changed TCU
5th, ReGrounded the grounds to the TCU.

After each thing that we did, the tranny came out of limp mode and shifted either for a few days or a day... This is puzzling us because everytime we think we get it, bang its back in limp mode... The last conclusion we came to, was whoever put the stereo in before I bought the car grounded the stereo at the same place the tcu was grounded.. So could it have possibly been interfeering with eachother? I didnt think that would matter, but it seemed to fix it when we moved them.. But after 200 Miles later, while doing 73 On cruise, it dropped back into 3rd.. Each time that we fix it, if it happens again, that thing that fixed it last time doesnt do a thing... Any help would be appreciated...

 

[Old Mitsu Tech]

Post the codes and their meaning. Hopefully they will give us some insight into what's happening.

Good Luck

 

[TheAdvocate]

Nevermind... After sitting over night and playing with the wires, it came back out of limp mode.. Something must be lose in the harnesses...

 

[TheAdvocate]

Ok, and after a day the car went back into limp mode. To check the codes, is it the White harness looking connector to the right of the steering wheel right underneath it that I use to check the tranny codes?

The dealership that I got the car from replaced the motor not to long after I had it.. I lost all confidence in them doing any mechanical work after needing to take it back to them 3 different times because they didnt test or check things well... But if they put a new motor in would that mess things up with my tranny? My tranny was shifting fine before they put the motor in and now Im having limp mode issues with it after i got it back. It started happening a little after a month of having it back. Is there a sensor that may have went bad from switching motors, or something not hooked up correctly?

 

[Wickedracer84]

tell me something guys how do u know when its in limp mode?
beacause my car could be doing the same thing?

 

[TheAdvocate]

You need to have an automatic first off.. But the car will only have (Park,Reverse,Nuetral, and 3rd gear) It wont shift down to first or second, and it wont go to overdrive or 4th... The tranny will shake when you shift into reverse or drive when its in limp mode... When you take off from a stop you won't have a very fast response because your in 3rd...

The check engine light will most likely come on after a little bit also... It will normally give you an internal tranny code, unless you have a computer to read from the tranny computer..

 

[Wickedracer84]

nope im not in limp mode ever than even tho i do have an auto

 

[tylor110986]

It sounds like my 91 gsx is in limp mode also. where is the tcu located i saw a gold box under the center console but it looks like there are two diff ones there. also i tried to check the codes and nothing happens.

 

[DSMboostin15]

I had the same problem with my '92 Laser. It would go in and out of limp mode, and I could not figure out what it was. So I pulled out my TCU and opened it up. One of the capacitors was fried and leaked all over the board, causing the TCU to fail. Brand new, these things are expensive, but if you go to the junkyard, you can probably fool the guys that work there and pay $20 like I did. I put the new one in and it worked perfectly until the day I sold the car.