zim

90 cherokee limited, 4 speed auto.
Today when I put her in D or OD and drive off, trany stays in 1st and 2nd gear. Ran thru all gears on shift selector and it won't come out of low gear??
Crawled under and had wife run thru gears, lever on side of trany moved thru all positions with the selector moves.
Going back out to look a little closer. Cables look good, has never acted frunny before, fluid level good?

any ideas where to start looking next? thank you.

cherokeeyed

Is the fluid too full? Have you run it on out in 2nd to see if it will shift to 3rd? Sometimes mine likes to hold 2nd for a little bit, get the rpms up and ease off the gas and it will shift. I know it's not normal but I've driven this thing all over and wheel it weekly and nothing has ever happened.

zim

Tried all that. Thanks though.

tjwalker

The AW4 is an electronically controlled transmission. The throttle position sensor is very important in providing input signals to the transmission and is directly involved in shifting characteristics. I'd recommend verifying it before moving onto more complex possibilities. Here is more courtesy of Cruiser54....
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RENIX TPS ADJUSTMENT

Before attempting to adjust your TPS be sure the throttle body has been recently cleaned. It's especially important that the edges of the throttle butterfly are free of any carbon build-up.

IMPORTANT NOTE: With the Key OFF, and using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector of the TPS. The letters are embossed on the connector itself. Touch the black lead of your meter to the negative battery post. Wiggle the wiring harness where it parallels the valve cover and also over near the MAP sensor on the firewall. If you see more than 1 ohm of resistance, or fluctuation in your ohms reading, some modifications to the sensor ground harness will be necessary. The harness repair must be performed before proceeding. I can provide an instruction sheet for that if needed.

MANUAL TRANSMISSION:
RENIX manual transmission equipped XJs have only a flat three-wire TPS mounted on the throttle bodyand it provides data input to the ECU. It has three wires in the connector and they're clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.

Sometimes, after adjusting your TPS the way outlined above, you may experience a high idle upon starting. If that happens, shut the engine off and reconnect your probes to B and C. Start the engine and while watching your meter, turn the TPS clockwise until the idle drops to normal and then rotate it back counterclockwise to your desired output voltage.

AUTOMATIC TRANSMISSION: RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a flat three-wire connector, same as the manual transmission vehicles have, and it is tested the same as the manual transmission equipped vehicles, as outlined above—FOR ALL ENGINE MANAGEMENT RELATED ISSUES.

However, the automatic TPS also has a square four-wire connector, clearly embossed with the letters A,B,C, and D. It only uses three wires and provides information to the Transmission Control Module. THIS SQUARE FOUR WIRE CONNECTOR IS USED FOR TRANSMISSION/SHIFTING RELATED ISSUES ONLY. Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your REFERENCE voltage. Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage. For example 4.8 volts X .83=3.98 volts. Adjust the TPS until you have achieved this percentage. If you can't, replace the TPS and start over. So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and the other side feeds the TCU.
FOR AUTOMATIC TRANSMISSION RELATED ISSUES: Check the square four-wire connector side of the TPS.
If you have ENGINE ISSUES check the flat three-wire connector side of the TPS.

For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.
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Also, verify your TV cable adjustment. Here is a link on "how-to" do that, very easy. Good luck and keep us posted!

https://www.cherokeeforum.com/f2/free-quick-fix-41821/

zim

OK. finally got time and a new tester. Made copy of the above information and am now going outside to raise the hood!!
I would rather change the trany than mess with troubleshooting wiring but here we go.

Live action coming. thank you tjwalker

zim

In the flat three wire connector,
reference voltage: 5.06 / output voltage:0
Going back to test the square 4 wire connector now.
be right back-----

zim

In the square four wire connector,
reference voltage: 4.69
output voltage: 0

any tips on where to go from here?

cruiser54

New TPS.

zim

Got it!! Just came in from a good long test drive. Runs like a beast! Shifts right everytime!

The funky zero readings I found out were operator error. I was not getting good connection when preforming the back-probing. (my wife thought that was really funny)

Once I figured out how to properly use my testor, we did all the above calculations and adjustments to determine the old TPS was indeed junk.

Put on the new TPS and followed the above instructions to get perfect readings. Fired it up and once again enjoyed normal shifting and rpms .

Many thanks to tjwalker! zim

cruiser54

Woohoo!!

zim

Thanks Crusier. I did learn to not be such a whimp about this electrical troubleshooting thru this. Between good people at sites like this and youtube vidios a guy can get some very good information and not get discouraged when he gets to that line in his Hanes book "It is best to contact your dealer" yeah right!

thanks again you all, zim

cruiser54

I'm glad you have gotten past your phobia on electrical stuff. It's not that bad, is it? I'll bet the wife is impressed......

zim

Crusier54, I been going thru your pink link and looking over all of that other pesky stuff that I have tended to shy away from. Next thing will be all new vaccuem lines!
Awsome bunch of information there at your link! thank you!

cruiser54

You are now obviously well equipped to tackle that stuff with confidence. My hope has always been that the write-ups would be a confidence builder.

http://learn.adafruit.com/multimeters/

Radi

Nice work Zim! Electrical stuff isn't too bad once you get your feet wet. (not that I'm advocating standing in a puddle while playing with electricity, lol)