KensPS

Car started going into limp mode a couple months back. I could pull the 7.5amp fuse out for a while, put it back in and all would be fine for a while. My 17 year old daughter is the primary driver of this car. Two weeks ago she calls, now its stuck in park, and wont come out of park. I explain the keyhole to her, she starts driving home and it has also gone into the limp mode at the same time. Its been two weeks because I have been recovering from surgury. During this time Ive read and checked that the tailights do indeed work, so brake position switch is ok. So last light I pull the fuse to hopefully reset everything. This morning comes and battery is dead. So I run downtown and get a new battery. In the meantime I had read about people with similar issues being fixed after a new battery being put in.
At first no change, still in limp mode and stuck in park. Back to computer for more reading. Found something about the possibility of the tps sensor connection getting dirty causing problems and high rpms makes light go out.
I started car, upon revving it up, at 2500rpm the green light would go out and come back on when it idles down. I unplugged battery, pulled tps connector apart and back together several times, tried to blow it out with air and put it back together and reconnected the battery.
I started it, tapped the brake and could hear the solenoid clickingnow, great.
Well, it worked great at first, ran a few errands, stop start and so on and thought wow, were all good. Got on the freeway and after a couple miles running 65, it tried to downshift and then back up a couple times.Went a few more miles and all was fine so I thought. I pulled off the freeway to the stop sign, and when I went to take off it was again in limp mode. I tried shutting it off, pulling the fuse for a bit, but it stayed in limp mode and now locked in park again. So it limped all the way home.
So when idling in driveway, no check engine light but Green S light stays on. I jumped the connector to try and get codes and nothing, the green light doesnt flash but while the connector is jumped, the check engine light comes on till you pull the jumper off. Also no flashing light on the tcu to try and get a code from there.
Any ideas, daughter really needs her car to work. Sorry so winded, just wanted to try and get all the details out the first time.
Thanks in advance.
Kenny

KensPS

Any ideas ???

MAD_MIKE

http://techauto.awardspace.com/transmission.html

KensPS

I've read that article. I can't get any codes. I opened up the tcu, no blown fuses or leaking capacitors? Yesterday I pulled the fuse, disconnected the battery and tried to reset everything. It didn't work. What I did get the first time I started the car was the solenoid under the shifter started going in and out.

Do you think this is all pointing at a failing tcu even though there are no blown fuses / capacitors??

Shouldn't there be a code at least if this is failing?
Thanks.

KensPS

What other model years besides a 1990 can I look for a used tcu to try??

PT-Tuner.com

The tcu on my 91 went out, replaced all the capacitors and burned resistors for less than $5.

Before Pictures:



After Fix:




Had to be a little creative with this, and bypass the original mounting holes, as the area was covered in carbon, and if were used again, would probably add extra unwanted resistance. I suspended the resistors in hot glue for several reasons; dampen vibrations, hold in place, and it can be easily pealed/removed in the future for whatever reason.

KensPS

Thats part of the confusion I have. I opened it up and I don't see anything that appears to be burnt out or leaking. Everything looks perfectly good inside??

PT-Tuner.com

Try replacing the capacitors regardless, if one hasn't died yet, its not long till one does; They can leak, they can short, and they can lose their rated capacity, any one of these can be detrimental to the operation of the tcu, and using a 92-93 tcu causes you to lose the "sport" mode functionality (if you like it / use it). Also wouldn't you prefer to not have to pull out the hot glue and be creative because something "flared" (my example). Mine went right as my car rolled over to 180k miles, exactly.