AW4 Code 45 shifting a bit off (97)

Hello all,
First time post for me. I've been a long time lurker with not much to add to the great tech advice here. Now I have a problem I can't fix!

So... the issue:
-1997 Cherokee, AW4.-
About a month ago the CEL came on and with the 3x key flip it shows a code 45. This is some kind of mystical code. But in reading many many lists of what the codes mean, I think it is the overdrive or torque convertor lock-up that is the problem. Probably the latter, because when I'm coasting, it seems to drop out of gear. As soon as I give it gas, rpm goes up to 2-2500 then it finds the right gear and it's all good. BUT, sometimes OD does not work at 100kmh when it should. It also starts in drive, which it shouldn't so the problem is causing the TCU to shut down. Otherwise, shifts fine through the gears, I have reverse lights (not NSS).

After a lot of searching I conclude this is an electrical problem, probably solenoid.

So far I have checked the obvious TPS with an analogue meter. The range is about 1-4V. The signal shows up at the TCU harness as well, so no broken wire there.

After checkin this page: http://www.transonline.com/transdigest/magazines/1997-10/Shift%20Pointers/index.html

I checked what I think are the three solenoid pins at the TCU harness. But the TCU harness is different on a 97. It has 13 horizontal pins. However, there are three pins next to one another that produce about an 8ohm resistance, what it should be... I think.

So I'm stumped from here. I have not put a scanner on it and the shops around here charge an hour just to hook it up, no freebies (in BC).

If anyone could suggest a next step I would really appreciate it. From my research it looks like I should take the pan off the trans and ohm to solenoids. But before I dig into it, I thought I'd check it out with yall.

Thanks!

The unlocking when stepping back down on the gas is normal. Mine does it every time. Overdrive usually is at about 45mph (on normal acelleration). I'd guess the code is from the NSS (FSM shows it to have a direct link to the #3 solenoid). Solenoids one, and two are off in overdrive, and three is what controls the T/C lock up. They all should be between 11-15 ohms. Looking at the plug from the TCM (lock on top little tab lower left corner plug has a roundish shape) top left is 1234 bottom is 5678.
CAV 2 is sol-B (#2) OR/WT
CAV 3 is sol A (#1) WT
CAV 4 is sol C (#3) DB/WT
Ground is eather the black wire, or though the transmission case. Its hard to tell. The solenoids are grounded through there cases.

My info is from a 2000 FSM so you may be different. I can't look up the CEL code because I have to use a scanner to read my codes. I can't use the key on off on off on trick.

Thanks a bunch.
I'll get into this as soon as it stops raining here and post the outcome.

After some rough weather, I was able to get working on this again.

I pulled the codes from the computer. p0700 & p0705
Code p0705 is the NSS. I took that apart, cleaned it, one code is gone.

Sadly, check engine light is not gone. The P0700 code is still there. That is a generic transmission fault code. The light is sometimes off when I start it but always comes on within 5 seconds. Yes, I have reset the computer.

Anyone have any additional ideas to offer?

I know of a speed sensor on top of the transmission case. How can I check that? Note the speedo sensor on the TC is fine at the dash speedo.

A recent post suggested someone w/ a similar problem check the transmission relay. Where is the transmission relay?

Finally, could a vacuum leak cause something like the above problem? What about wrong fluid type or level?

anyone...anyone?
Tx.

Hello, I'm resurrecting an old thread of mine.

Does anyone know if there is a relationship between the cruise control system and the tps? If not, is does the cruise system only informed by the vacuum?

I probably need a new tps, based on my symptoms. But I'm not sure b/c the tps voltage readings vary as they should on the meter.

Cruise is buggered, and it died around the time the CEL came on. So either a vacuum or tps is causing that. I was thinking it was vacuum b/c when rpms are high cruise engages, suggesting there is a small vacuum leak. On the other hand, it could be that the tps resistor is worn at a normal throttle level.

THANKS IN ADVANCE!

UPDATE:

A new tps solved the problem and eliminated ALL the funny shifting. Jeep now shifts and idles like it should. THE JEEP NO LONGER INDICATES ERROR CODE 45.

A GOOD METER READING DOES NOT = GOOD SENSOR:
I checked my old TPS with an analog meter and there was a smooth + linear voltage increase all the way through rotation of the sensor. Despite this, the sensor was still garbage.

im having the same problem with my shifting but no check engine light is coming on, can a shop still pull codes from the computer?

Usually when RPM's are higher, vacuum is lower..... That's what the vacuum canister is there for.

odd.