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View Full Version : DSM Guys...Limp Mode Issue..


Elbow
07-07-2009, 02:37 PM
I have a 92 Laser turbo, it's A/T, FWD, it is in limp mode, aka stuck in 3rd gear, has P,N,and R, but no forward gears but 3rd (no matter what "gear" I put it in, it's 3rd.)

I have reset the ECU, I have started tracing some wires, now have the TCU out and am inspecting it. See pics, does it look bad? If so, repairable? I know there are manual shift boxes that bypass the TCU's limp mode function.

Also the speedometer quit working, but it was in limp mode before that. Is that going to send an error? BTW there are no codes, and no CEL.

http://i6.photobucket.com/albums/y237/simontibbett/LivingRoom061.jpg

http://i6.photobucket.com/albums/y237/simontibbett/LivingRoom063.jpg

http://i6.photobucket.com/albums/y237/simontibbett/LivingRoom065.jpg

http://i6.photobucket.com/albums/y237/simontibbett/LivingRoom068.jpg

http://i6.photobucket.com/albums/y237/simontibbett/LivingRoom069.jpg
TSiFTW
07-07-2009, 02:48 PM
Looks to be the TCU. Around this age they and the ECU start to go bad a lot. Notice the burn marks, those are usually bad. Just to make sure have you hooked up an auto timer or anything that you had to mess with wiring? That will often cause a limp mode also.
Elbow
07-07-2009, 02:49 PM
I checked the ECU it's clean inside, and has a marking, looks to be a used replacement.

I was worried about those burn marks. Nothing has been added. The owner before the PO did have some ghetto rigged stereo wires and such, but I think I got most of those removed, and checked all fuses.
Barefoot
07-07-2009, 02:53 PM
it is toasted. spring for a remaned. dont get a used 1 with just as much age on it.
TSiFTW
07-07-2009, 02:54 PM
Looks to be the TCU. Around this age they and the ECU start to go bad a lot. Notice the burn marks, those are usually bad. Just to make sure have you hooked up an auto timer or anything that you had to mess with wiring? That will often cause a limp mode also.


I reread and see that you probably dont have an auto timer. I would say probably your TCU then. They are repairable if you are knowledgable with working with electronics. Most people just get a new one.:goodjob:
Thighs
07-07-2009, 02:54 PM
^^ im with that guy
Elbow
07-07-2009, 02:55 PM
Yeah I will go find one, or I have read you can get a manual shift box and it bypasses the TCU's need for limp mode?
TSiFTW
07-07-2009, 02:57 PM
it is toasted. spring for a remaned. dont get a used 1 with just as much age on it.

Like he said get a reman one. The ecu and TCU are at the age to start failing, so most likely a used one won't last long.
Elbow
07-07-2009, 02:59 PM
I think they are like $250 for that if a manual shift box is less and will fix the issue I'd personally rather do that. Or figure out how to make one lol.