Everything you ever wanted to know about the AW4

[kastein]

So at this point you've got a 98+ tone ring, sensor, and TCU, right? I would expect that to work. Not the 97 TCU and a 98+ tone ring and sensor combined? Because if you have that setup and it works I am going to be very confused.

Thanks for the update, I'll add it to the OP. My apologies about the info in this thread misleading you!

 

[Milner]

Yes, everything is currently 98
BUT When I got in it to drive last night the CEL came on as soon as I turned the key!!
It still drives/shifts/locks up as it should.
If I clear the code the CEL stays off while driving, but as soon as I turn the ignition off and back on the CEL is back on even BEFORE the motor is started.
Always the P0700 and most of the time the P0720 (OSS)
It seems fine, but I can not get the emission test done with a CEL.
I am at a lost at this point!!
ANY ideas????

 

[kastein]

WTF???

I am real confused now. P0720 is a circuit malfunction at least, not a ratio mismatch or something, so you are looking at an electrical fault of some nature and all the parts are lightweight and easy to wrestle with. I am guessing an intermittent connection or maybe the OSS is bad. Check for bad connections first, especially after all this splicing and swapping. The fact that it does it without starting the engine or moving the vehicle (turning the output shaft) tells me you probably have an open circuit, a short circuit, or an intermittent connection somewhere in the wiring to that sensor.

P0700 is the generic "something's wrong with the trans control system" so ignore that one till you have the P0720 licked. Might want to double check that your NSS is properly aligned however, though that usually causes a P0700 and a P0705. It's easy and fast though so you lose nothing by checking it.

You have had a real rough time with this one, I have never seen anyone get this unlucky with an AW4 control system.

 

[Sidewinder CC]

Milner,

Do some checks at your TCM connector.

Below are the TCM pin out and check procedures.

You are interested in the OSS Resistance tests. You'll be dealing with pin cavities 3 and 4. Use a safety pin, or equivalent, as a probe in the pin cavities.

You may want to check for voltage at pin cav 3 and 4 with the ignition switch turned to RUN. And check for short to ground at pin cavities 3 and 4.

Before you start, here are the possible causes for a P0720:

P0720-OUTPUT SHAFT SPEED SENSOR ERROR

When Monitored: Continuously with the vehicle speed over 6 MPH (over the CCD bus) and the transmission is in a forward gear (1st, 2nd , 3rd or OD).
Set Condition: No signal from the Output Speed Sensor for 100 seconds.

POSSIBLE CAUSES
INTERMITTENT WIRING AND/OR CONNECTORS
OUTPUT SPEED SENSOR GROUND CIRCUIT OPEN
OUTPUT SPEED SENSOR SIGNAL CIRCUIT OPEN
OSS SIGNAL CIRCUIT SHORTED TO OSS GROUND CIRCUIT
OUTPUT SPEED SENSOR GROUND CIRCUIT SHORT TO GND
OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
OUTPUT SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE
OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
OUTPUT SPEED SENSOR (OUT OF RANGE)
TCM-OUTPUT SPEED SENSOR

TCM pin outs:

Test procedures:

The OSS wiring passes through the black connector shown in the pic below.

Verify the wiring from the connector to the transmission is not chafed and shorted to ground.

.

 

[Milner]

Sidewinder you are AWESOME.
I figured the same....a wire issue since I don't even have to start it to trigger the code.
I will get the meter out and start testing.
THANKS All!!

 

[Sidewinder CC]

If you do (or do not) find a fault when doing the tests, see if you can get a helper to wiggle the wires while you monitor the readings.

The wires that go from that connector by the firewall down to the transmission live in a hostile environment and so do the wires going over the transmission to the OSS, so I would suspect a fault in these areas.

With all the work you've done there's a possibility a wire got pinched in the process.

 

[Milner]

Well, I probed all the wires and tested as per instructions above. Everything tested on fine. So I pulled the ISS and OSS to check them against each other.i They tested the same, but switched them anyway. Then I pulled the plug down and check all the wires for continuity. All checked good.

First start no CEL, but several codes from have key on and TCM unplugged.
Cleared them and it drove fine. Still no cell. But when scanned I still got an OOS code, and TC code, and a 1st gear solenoid code, CEL. Drove it a couple times, cleared the codes a couple times.
As of right now I have a few short drives and no codes.
Some theories;1-Trans harness plug under the hood has issues, 2-TCM is bad/has a short or plug is bad,
3- I notices about 3" of the wires at the firewall plug were not loomed and were touching the #6 plug wire. I wonder if this could cause some jumping and bad signals to the TCM?? So I loomed it and loomed the plug wire.
At this point it is working and no codes, but who knows tomorrow????

Thanks for all the help!! I will continue to update so if anyone else every runs into similar issues.

 

[Milner]

I am continuing to get the trans codes about 1 out every 3 times I drive it, but not CEL. I tried to get the emissions test done, but it failed and the shops testing equipment did not give a specific reason for the fail. I assume the codes were present. I scanned it when I left and they were back. (I am in an OBD2 only emissions test county.)
Still shifts and drives fine.
I still suspect a wiring issue.
My thinking is that I get the codes because of a momentary loss of signal, but it then continues to work, so no CEL (Does this sound right?)
Next step, junk yard TCM and trans harness??
If I can get the EM to pass I will just drive it and see, but right now I can't license it.

 

[MikeT4]

WTF???

I am real confused now. P0720 is a circuit malfunction at least, not a ratio mismatch or something, so you are looking at an electrical fault of some nature and all the parts are lightweight and easy to wrestle with. I am guessing an intermittent connection or maybe the OSS is bad. Check for bad connections first, especially after all this splicing and swapping. The fact that it does it without starting the engine or moving the vehicle (turning the output shaft) tells me you probably have an open circuit, a short circuit, or an intermittent connection somewhere in the wiring to that sensor.

P0700 is the generic "something's wrong with the trans control system" so ignore that one till you have the P0720 licked. Might want to double check that your NSS is properly aligned however, though that usually causes a P0700 and a P0705. It's easy and fast though so you lose nothing by checking it.

You have had a real rough time with this one, I have never seen anyone get this unlucky with an AW4 control system.

I would like to send you a PM but you PM box is full.
Could you send me a PM so I might have a way to contact you.

Thanks
MikeT

 

[ktfung]

Re: Can you swap a 1999 AW4 to a 1996 ?

Hi, I got a 1996 xj 4x4 with a AW4 transmission slipping bad and transmission shop said it need a complete overhaul . A friend of mine has a 1999 xj 4x4 recently roll over his jeep a few times and decided to parting it out . I read about If you have a 1990.5-1996 XJ:

1998-2001 AW4s require more work. All the transfer case input gear info from 1990.5-1997 applies, on top of that, the sensors have changed! You can either build the circuit given here by lawsoncl or swap the transmission tail housing, sensor drive rotor, and output speed sensor as shown here by Frank Z to make this work. You may need to add custom wiring for the transfer case indicator lamps . < there is no problem for me to swap the tail housing sensor drive rotor, and output speed sensor and reuse the 96 transmission wiring harness for the 99 AW4 and transfer case lamp >

However for the 99 AW4 near the bellhouseing have a front input sensor ( vehicle speed sensor ) but the 96 AW4 dont have that machined bore hole in the transmission housing for the front sensor . The place where i live dont require annual emission inspection any more so I don't need to worry about CEL being on due to missing the front sensor input signal . My main concern is that will the transmission work and shift normally without that front VSS ? or any one had done a swap from a 1998-2001 AW4 to a 1996 successfully ?

Thanks in advance

 

[Redrockracer1019]

Hello. I'm just as dumb as the rest of us. I got turned on to this site today from a fourm question I had started on Comanche club.com

I have a 1990 4x4 Comanche
The motor is bad
I bought a 2000 Cherokee 2wd 4.0 HO

I Am in the middle of swapping the Cherokee motor in to my Comanche...
My Comanche its titled 1990 it has an aw4 an np231...
How do I install the motor an run my transmission? Do I isolate the obd1 trans wireing from the body wireing an run the 90's aw4 controller or is it possible to swap the Cherokee dashboard an all the harness an just adapt the sensors at the trans.. I'm in the dark here.. I have a 90 trans an t case an a 2000 engine how do I mold the 2 as 1??? Thx

 

[2001 RED XJ]

I'm having a issue with my 01 jeep cherokee. Not sure if this is transmission related or its my new motor I recently got installed. My jeep shifts and runs good during normal driving but if I floor my jeep at 45 it will gain speed until I get to 65 and then it falls flat on its face. It doesn't sleep gears or anything. Its like someone puts the brake on and it will not gain anymore speed until I let off the gas a little and then it will shift into 3rd gear. It will not shift into 3rd when the gas is to the floor. And yes I have adjusted the kickdown cable.

 

[xeroOTG]

Re: Can you swap a 1999 AW4 to a 1996 ?

Hi, I got a 1996 xj 4x4 with a AW4 transmission slipping bad and transmission shop said it need a complete overhaul . A friend of mine has a 1999 xj 4x4 recently roll over his jeep a few times and decided to parting it out . I read about If you have a 1990.5-1996 XJ:

1998-2001 AW4s require more work. All the transfer case input gear info from 1990.5-1997 applies, on top of that, the sensors have changed! You can either build the circuit given here by lawsoncl or swap the transmission tail housing, sensor drive rotor, and output speed sensor as shown here by Frank Z to make this work. You may need to add custom wiring for the transfer case indicator lamps . < there is no problem for me to swap the tail housing sensor drive rotor, and output speed sensor and reuse the 96 transmission wiring harness for the 99 AW4 and transfer case lamp >

However for the 99 AW4 near the bellhouseing have a front input sensor ( vehicle speed sensor ) but the 96 AW4 dont have that machined bore hole in the transmission housing for the front sensor . The place where i live dont require annual emission inspection any more so I don't need to worry about CEL being on due to missing the front sensor input signal . My main concern is that will the transmission work and shift normally without that front VSS ? or any one had done a swap from a 1998-2001 AW4 to a 1996 successfully ?

Thanks in advance

I did one in a 93(?) And I used the 98 tcu. I made an adapter by desoldering the header from the 93 tcu and splicing the 98 wiring harness plug into it. I had to do some sensor wiring additions for the new sensors, but once that was done, all shifted well. For me, wiring is easier than mechanical work, so it was easy. It depends on how good you are at reading FSM wiring diagrams.

 

[xeroOTG]

Hello. I'm just as dumb as the rest of us. I got turned on to this site today from a fourm question I had started on Comanche club.com

I have a 1990 4x4 Comanche
The motor is bad
I bought a 2000 Cherokee 2wd 4.0 HO

I Am in the middle of swapping the Cherokee motor in to my Comanche...
My Comanche its titled 1990 it has an aw4 an np231...
How do I install the motor an run my transmission? Do I isolate the obd1 trans wireing from the body wireing an run the 90's aw4 controller or is it possible to swap the Cherokee dashboard an all the harness an just adapt the sensors at the trans.. I'm in the dark here.. I have a 90 trans an t case an a 2000 engine how do I mold the 2 as 1??? Thx

Isolate the 90's tcu wiring unless you got a complete 2000 harness and TCU. It does not need to "talk" to the ECU but you might need to have it flashed to a manual ECU so you don't get a CEL.

 

[xeroOTG]

I'm having a issue with my 01 jeep cherokee. Not sure if this is transmission related or its my new motor I recently got installed. My jeep shifts and runs good during normal driving but if I floor my jeep at 45 it will gain speed until I get to 65 and then it falls flat on its face. It doesn't sleep gears or anything. Its like someone puts the brake on and it will not gain anymore speed until I let off the gas a little and then it will shift into 3rd gear. It will not shift into 3rd when the gas is to the floor. And yes I have adjusted the kickdown cable.

I'm struggling to understand what's going on here. Sounds engine related though, like a plugged cat maybe? What caused the old engine to fail?

 

[cracked-butt]

Great thread! Will come back and read all the pages (32!) to find if the info im looking for is in here. 93 2wd 4.0 HO (2door as well!) wanting to do a "bolt in" t-case (prefer the p-242) to make it a (cough cough) "real jeep". It has the Chrysler 8.25 rear differential. Need to check the gear ratio. To make sure I get the correct front differential (gearing).

 

[Redrockracer1019]

Isolate the 90's tcu wiring unless you got a complete 2000 harness and TCU. It does not need to "talk" to the ECU but you might need to have it flashed to a manual ECU so you don't get a CEL.

If I swap the entire 2000 xj harness in to my 90 Comanche how do I adapt the 90 aw4 to the harness what do I do just splice in the Leeds to the speed ensors what about the valve body pig tail is weird?... Does it matter the xj is 2wd... I'm thinking about completely gutting the Comanche out tommorow an start swapping in the whole Cherokee an see what happins?

 

[xeroOTG]

If I swap the entire 2000 xj harness in to my 90 Comanche how do I adapt the 90 aw4 to the harness what do I do just splice in the Leeds to the speed ensors what about the valve body pig tail is weird?... Does it matter the xj is 2wd... I'm thinking about completely gutting the Comanche out tommorow an start swapping in the whole Cherokee an see what happins?

I honestly do not remember. I pulled it off in my 93, which would be very similar. When I did it, I used a FSM. It was not hard, just fairly time consuming. The aw4 controller is fairly simple, it takes an input from the throttle position sensor, monitors the brake petal, transmission position sensor, and the output speed sensor (not the speedo drive). For the tps and the brake, it just sits in parallel to the other systems, so making it isolated should be fairly simple.

The tps adjusts the shift points and the brake petal is used to unlock the torque converter, so don't skip those inputs. Without them the TCU will function poorly.

 

[2001 RED XJ]

Old motor had a cracked head. Converters are not plugged. We unbolted the exhaust. The jeep will not shift into third when I gas pedal is to the floor. If I let off a little it will shift into third. Something is preventing the jeep to accelaerate past 65.

 

[DieselSJ]

Old motor had a cracked head. Converters are not plugged. We unbolted the exhaust. The jeep will not shift into third when I gas pedal is to the floor. If I let off a little it will shift into third. Something is preventing the jeep to accelaerate past 65.

Stop posting your problem into multiple threads. You already have 2 threads going for this. Listen to what we are telling you in the other threads. You are NOT having a transmission problem.