Another AW4 that wont shift

My 1989 XJ doesnt want to shift till the rpm gets real high. I disconnected the TCU and it shift as it should, like a manual without 2nd. I checked the TPS, there is no 5v at the TPS. I checked for 5v at the TCU and no 5v at pin D1. I put in a TCU from the junk yard and same problem. Could I have another bad TCU. Also all other inputs to TCU are correct. AM I correct in assuming that the 5v to the TPS comes from the TCU or am I missing something.
Randy

Have you checked the inline fuse for the TCU. It is located on the passenger side under the dash. It's easily identified by the heavy gauge bright yellow wire!

Yes fuse is good.

Another AW-Shifting kit needed!
http://www.awshifting.com/

I believe you have a break in the wiring somewhere, the tcu's seldom go out

TRB said:

Yes fuse is good.

Click to expand...

There is also a fuse in the lower left of the fuse block marked "trans" that supplys power for the brain side of the TCU.

Both fuses are good. 12volts at pin D14 and D16 with key on. All 12volt inputs work like they should. Still no 5volt output on D1(goes to TPS). MyTCU has wires to connector C4 an C5 which makes 16 total wires to TCU. I can only find information to identify 14 wires. Does anyone know what C4 and C5 is. I know that C5 is ground, by testing with a meter.

Is there a difference in the TCU for a 88/89 and say a 91 or 93 model. My 89XJ had a TCU that appears to be from a 91 (it had 91 on the case lid). I got one from the junk yard out of a 93. The jack on the TCU from the 91 and 93 is slightly different than the plug on the cable. The jacks are keyed to keep you from pluging them in backwards. The keying is slightly different on the 91/93 from my plug. They will plug in but it doesnt look right. I just picked up another TCU and it is from an 88 and the jack on the TCU is identical to the plug on the cable.
Randy

TRB said:

Both fuses are good. 12volts at pin D14 and D16 with key on. All 12volt inputs work like they should. Still no 5volt output on D1(goes to TPS). MyTCU has wires to connector C4 an C5 which makes 16 total wires to TCU. I can only find information to identify 14 wires. Does anyone know what C4 and C5 is. I know that C5 is ground, by testing with a meter.

Click to expand...

I might also add that the 5vdc is between D1 and D3 not D1 and ground.

I checked it both ways and still no 5v.
Langer1, was there an atachment with your previous. I so I didnt get it.
Randy

TRB said:

I checked it both ways and still no 5v.
Langer1, was there an atachment with your previous. I so I didnt get it.
Randy

Click to expand...

I don't understand?

Langer1, I didnt see the diagram on my laptop at work. I see it now on my computer at home, Thanks.

I think I got this figured out. It seems that in 91 jeep made a change. They quit using the ECU and started used a PCM. Prior to 91 while using the ECU they used a dual throttle position sensor. One for the ECU and one for the TCU. They were different logic is probably the reason for two. One went low as accelerator was depressed and the other went high as accelerator was depressed. Prior to 91 the TCU provided the 5 volts for one TPS and the ECU provided 5volts for the other. In 91 when they changed to the PCM and only one TPS they didnt need the 5 volt supply for the TPS from the TCU, so I can only assume they took it off the board since I had same problem with boards from both years, 91 & 93. So when I installed the TCU from an 88 the 5 volts is there and everything works.

Your diagram and almost every other diagram I have seen must be pre 91. I ran across a diagram on another web site that showed one TPS going to both PCM and the TCU. So I started digging in my Chiltons. And sure enough it show a change in 91 from ECU to PCM.

If you would have originally told us you used a tcm from a different year we all could have saved you a ton of checking, the computer systems changed in 1991 from renix to ODBI, a littel more info to start with would have been nice and saved you tons of work

The good thing is that 172 people viewed this thread and I bet someone learned something.

langer1 said:

The good thing is that 172 people viewed this thread and I bet someone learned something.

Click to expand...

well I know I looked at it about 20 times myself to see what info changed

Yeah:

give full info on all parts in your openning statement

dont assume different years use the same parts

remember the renix to odb change in 91 and up..........parts seldom interchange

Read post #8, it states different year models, but you are correct I should have said that originally. At the time I didnt think it made a difference my mistake.
Randy