AW4 TC lock-up problem

Hi guys,

as a new owner of an old XJ Cherokee M/Y 1990 4.0 liter Automatic, I have faced a lot of problems. A week ago I converted my old ABS-brake system to conventional non abs and on test drive I noticed that I have lost TC lock-up. Maybe just this happened at the same time ? Anyway I have search different forums and performed all the tests I have found. Everything else seems to be OK, but on TCU I get battery voltage to pin C 9 when shifter lever is in 3, but 0 volts in D. According AW4 trouble shooting I should get 12V on Drive. Is this correct and if not any guess ? Also when driving without TCU converter won't lock. On test program they tell that you can measure TC solenoid resistance from D7/C14 TCU unplugged and inginition off, but I get 13,4 ohms only when key is on. Wrong measurement.

So if you have any idea if my procedure is done wrongly let me know and give me more guidance...I have followed Wayne Colonna's AW4 doagnoses.

Regards

Jussi

Wow you know more about it than me. Bump ya up to the top. One of these crazy cats prolly know.

Hello professors and all the other tranny experts....I can't be the only one who have faced this measuring problem....

Jussi

Only thing I have to offer is to make sure the TCC release switch above the brake light switch didn't get unhooked or out of adjustment when you did the abs swap.

Problem is solved !!!!

According your suggestion I checked TCC again and found out that is was time to time inoperative. One reason are worn nylon bushes on brake pedal which causes slight extra movement so that the switch wasn't straight on line. Also when I renewed brake system, brake pedal was swinging loose and maybe the switch assembly was a little bent. When I measured TCC from TCU pin C10, it was OK, but during driving it was sending battery voltage to TCU and that caused that OD problem. I bent switch carrier slightly forward and now everything works. YESSSS

I also checked TPS and noticed that in my Jeep reference voltage is 5.45 V and TPS b-terminal voltage was 4.62 V. Someone wrote that correct voltage is 82 % on reference, but 4.50 V was the lowest I could have without too high idle . Full open voltage is 0.91V, it was before 1.16 V. I also noticed during the test drive that also tranny stands higher rev before OD locks off . Now the car is much more comfortable on motorway because I can speed up reasonably well without OD off.

So if someone else have similar problems, just follow page 3 http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html

Regards

Jussi

Jussi glad you are on the forum. WELCOME.