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  #1  
Old May 28th, 2010, 11:15
amp7876 amp7876 is offline
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98 aw4 tc lockup switch

I have searched and come up with conflicting answers.

Can you wire the 97 plus tcu to lock up the tc?
One article says a check engine light will trigger
another says you can not do it all, yet another says it will work.

One article says the 97 and up does not have a seperate tcu.

So what is the verdict can this be done successfully on the 97 up aw4?

-away
Thanks
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  #2  
Old May 28th, 2010, 11:17
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CJ~Abuzer CJ~Abuzer is offline
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Re: 98 aw4 tc lockup switch

This kit is designed to work with the 97+ without triggering the check engine light....

http://www.montanafab.com/aw4_trany_overide.php
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  #3  
Old May 28th, 2010, 11:48
amp7876 amp7876 is offline
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Re: 98 aw4 tc lockup switch

not really concerned about the check engine light.
Just concerned with reasons people say it can't be done on the 97 up.
Check engine light is already on for another reason, "no 02 sensor"
Thanks for the link though, they have a couple of great ideas.
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Old May 28th, 2010, 12:27
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Re: 98 aw4 tc lockup switch

It will work, you can do it, it will turn the CEL on. You just want TC lockup and no gear switching? That's pretty odd, the stock unit does a decent job of keeping the TC locked at the right times, most people want to shift manually instead.

If you want to avoid the CEL coming on, wire like so:


The switch is a standard 3-position slide switch you can find at most electronics stores that aren't Radio Shack, you should also be able to find them online in various places, let me know if you need a part number and a recommended distributor.

With the switch in the top position the torque converter will lock up when the TCU wants it to. With it in the middle position the torque converter will always be off. With the switch in the bottom position it will be locked on.

You *might* have to replace that 100 ohm, 5 watt resistor with a 12 ohm, 20 watt resistor, but I'm pretty sure a 100 ohm will be enough of a current draw for the TCU to be happy.
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Please do not PM me about the AW4 info thread unless you have a truly unique question that is not covered by it or info to add. I do not respond to questions answered by the thread.
Definitely do not hunt down my phone number at 3AM, text me about it, and then threaten violence when I am not helpful. It will not get you what you want.
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  #5  
Old May 28th, 2010, 12:46
amp7876 amp7876 is offline
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Re: 98 aw4 tc lockup switch

No i want both. Just did not want to complicate it. Figured if I could do one i could do the other.


I am familiar with circuits etc... but after reading multiple things on the net, i had some conflicting info.
I have access to all the electrical items needed, I am a distributor.
I happen to be screwing around at work looking for another weekend project and was going to pick up the items needed before leaving for home.
The XJ is sitting in the garage so i could not go look at it.

Thanks again.
Tony

Last edited by amp7876; May 28th, 2010 at 12:54.
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  #6  
Old May 28th, 2010, 12:59
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Re: 98 aw4 tc lockup switch

Yes you can. I have a custom shifter with tq lockup. It does not lock the converter in 1st or 2nd though, only 3rd and od.
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  #7  
Old May 28th, 2010, 13:00
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Re: 98 aw4 tc lockup switch

ah, cool! Good luck then. Didn't realize you were familiar with electronics
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Please do not PM me about the AW4 info thread unless you have a truly unique question that is not covered by it or info to add. I do not respond to questions answered by the thread.
Definitely do not hunt down my phone number at 3AM, text me about it, and then threaten violence when I am not helpful. It will not get you what you want.
CTeunuch: Sometimes I really wonder if this sport makes you insane, or it just attracts the mentally unstable.
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Old July 12th, 2010, 08:11
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by kastein View Post
It will work, you can do it, it will turn the CEL on. You just want TC lockup and no gear switching? That's pretty odd, the stock unit does a decent job of keeping the TC locked at the right times, most people want to shift manually instead.

If you want to avoid the CEL coming on, wire like so:


The switch is a standard 3-position slide switch you can find at most electronics stores that aren't Radio Shack, you should also be able to find them online in various places, let me know if you need a part number and a recommended distributor.

With the switch in the top position the torque converter will lock up when the TCU wants it to. With it in the middle position the torque converter will always be off. With the switch in the bottom position it will be locked on.

You *might* have to replace that 100 ohm, 5 watt resistor with a 12 ohm, 20 watt resistor, but I'm pretty sure a 100 ohm will be enough of a current draw for the TCU to be happy.
kastein,

Have you verified that this technique works to prevent the CEL from coming on when using an aftermarket manual shifter on a 97+ XJ? I've seen some speculation elsewhere in this forum, but I haven't seen anyone claim to have actually tried it.

I have Rail Shifter on order with RADesigns Products (should be here any day now!), and I was hoping to employ this technique using 3 20-ohm 25W resistors acting as dummy loads. I REALLY want this to work WITHOUT the TCM/DCM throwing a code and turning on the dreaded CEL.
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  #9  
Old July 12th, 2010, 08:13
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kastein kastein is offline
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by raneil View Post
kastein,

Have you verified that this technique works to prevent the CEL from coming on when using an aftermarket manual shifter on a 97+ XJ? I've seen some speculation elsewhere in this forum, but I haven't seen anyone claim to have actually tried it.

I have Rail Shifter on order with RADesigns Products (should be here any day now!), and I was hoping to employ this technique using 3 20-ohm 25W resistors acting as dummy loads. I REALLY want this to work WITHOUT the TCM/DCM throwing a code and turning on the dreaded CEL.
I have not.

However... I got the CEL to go out on my 98 recently! Only a few more fixes and it is inspectable. Expect testing in the near future now that I have a rig to do it on without driving to a friend's place and worrying about blowing theirs up.
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My yard looks like Sanford & Sons.
Please do not PM me about the AW4 info thread unless you have a truly unique question that is not covered by it or info to add. I do not respond to questions answered by the thread.
Definitely do not hunt down my phone number at 3AM, text me about it, and then threaten violence when I am not helpful. It will not get you what you want.
CTeunuch: Sometimes I really wonder if this sport makes you insane, or it just attracts the mentally unstable.
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  #10  
Old July 12th, 2010, 08:19
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by kastein View Post
I have not.

However... I got the CEL to go out on my 98 recently! Only a few more fixes and it is inspectable. Expect testing in the near future now that I have a rig to do it on without driving to a friend's place and worrying about blowing theirs up.
Really? How did you do that. In my brief testing this weekend, I had a devil of a time getting the CEL to go out once I set it by disconnecting the TCM from any/all of the three tranny solenoids. I was hoping to find a way to do it without having to disconnect the battery. I'd love to know your secret!

If I can find the resistor locally, I hope to test them out this week -- schedule permitting. I'll be sure to post my findings.
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  #11  
Old July 12th, 2010, 08:22
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kastein kastein is offline
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by raneil View Post
Really? How did you do that. In my brief testing this weekend, I had a devil of a time getting the CEL to go out once I set it by disconnecting the TCM from any/all of the three tranny solenoids. I was hoping to find a way to do it without having to disconnect the battery. I'd love to know your secret!

If I can find the resistor locally, I hope to test them out this week -- schedule permitting. I'll be sure to post my findings.
Sorry to confuse - I bought the vehicle as a "some assembly required" project. It had a really, really bad radiator, a broken wire in the coolant temp sensor wiring, no e-fan, a bad upstream O2 sensor, and the interior was disassembled / airbags weren't connected when I got it. It also had a problem in the evap system. "getting the CEL to go out" involved fixing all of that - I bought it as a replacement for my '96 and also as a prototyping rig for all the stuff I've been trying to design. Just had to get it back to OEM condition before starting on everything, otherwise I wouldn't know if the problems I was seeing were due to pre-existing conditions or due to a mistake in my designs.
__________________
My yard looks like Sanford & Sons.
Please do not PM me about the AW4 info thread unless you have a truly unique question that is not covered by it or info to add. I do not respond to questions answered by the thread.
Definitely do not hunt down my phone number at 3AM, text me about it, and then threaten violence when I am not helpful. It will not get you what you want.
CTeunuch: Sometimes I really wonder if this sport makes you insane, or it just attracts the mentally unstable.
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  #12  
Old July 12th, 2010, 08:32
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raneil raneil is offline
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by kastein View Post
Sorry to confuse - I bought the vehicle as a "some assembly required" project. It had a really, really bad radiator, a broken wire in the coolant temp sensor wiring, no e-fan, a bad upstream O2 sensor, and the interior was disassembled / airbags weren't connected when I got it. It also had a problem in the evap system. "getting the CEL to go out" involved fixing all of that - I bought it as a replacement for my '96 and also as a prototyping rig for all the stuff I've been trying to design. Just had to get it back to OEM condition before starting on everything, otherwise I wouldn't know if the problems I was seeing were due to pre-existing conditions or due to a mistake in my designs.
Gotcha. I tried various strategies, with limited (and un-repeatable) success. Once, I got the CEL to go off after having pulled the fuse in the Power Distribution Block that supplies Bat+ to the TCM (motor off). However the 2nd (and 3rd, and 4th...) time I tried that, it didn't work. I'm still not sure why. Obviously, I'm missing something.

The 2nd time I got it to go off (and stay off) was purely by accident. I was attempting to retrieve the code that had been set. I cycled the key 3 (or 4?) times hoping to see the code on the odometer or via CEL flashes. Instead, I got no code at all and the CEL went OFF. I started the Jeep, and the CEL was off and stayed off. I did not have the chance to repeat that procedure to see if worked again.

Good grief.
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  #13  
Old July 13th, 2010, 13:59
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raneil raneil is offline
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Success!

**Not sure if this should be posted here or in a separate thread. I'll start here and re-post elsewhere if requested/required.**

I performed a few experiments last night, and was very pleased with the results. While I still have a few more tests to run, the important questions have been answered in the affirmative. And that means I will be able to install a full-featured aftermarket manual shifter in my XJ (98 model, stock 4.0L & AW4) that will not set a diagnostic code and/or light the CEL.

I received my RADdesigns Rail Shifter yesterday, and set straight to work. First, I needed to confirm two things on which my plan depends:

1. Can simple resistors be connected between the 3 solenoid outputs of the Transmission Control Module (TCM) and ground to act as dummy loads without the TCM throwing a code and lighting the CEL?

Yes. This was tested by simply cutting the 3 solenoid output wires in the harness near the TCM plug, and directly wiring a 12 Ohm, 50W resistor between each wire (on the TCM side, obviously) and ground. Started the Jeep and waited. Drove up and down the driveway a few times. No CEL. No problems. It works!


2. Can the TCM be switched back and forth between the dummy resistors and the tranny solenoids with the motor running and the transmission in gear without the TCM throwing a code and lighting the CEL?

Yes. This was tested by using the schematic below. A DPDT relay is used to switch each TCM solenoid output between the real and dummy loads. Note the break-before-make configuration assures that the TCM output transistors never see both loads simultaneously, which would obviously double the current draw. They do, however, see no load at all for a fraction of a second -- and that's what this test was all about. Would that brief no-load condition cause a code/CEL? Fortunately, it did not. The relays are controlled by rocker switches. Drove around the block several times, switching back and forth between manually sifting with the RADesigns Rail Shifter, and letting the TCM do it's full-auto thang. No CEL. No problems. It works!


I ran out of time, and was unable to hook up and test the TC part (orange wires, SW3, RY3, etc.), but it should work fine. It's fundamentally the same circuit.

A few additional observations:

1. Manually shifting the AW4 is SWEET. Now I understand why so many have reported in these forums that they actually prefer shifting it manually, even during daily driving. It's something you simply have to experience first hand.

2. The RADDesigns Rail Shifter is smaller than it appears online. It should be easier to mount/locate than I had feared.

3. The 12 Ohm resistors get really hot. I'm hoping that kastein's theory is correct, and that higher value resistors can be used to reduce current draw. Using the metal knee blocker under the steering column as a heat sink will probably alleviate the problem, but using higher-Ohm resistors would make for a far more elegant solution, if they work. Will test and advise.

4. The schematic can be easily adapted for use with any sort of manual shifter and/or a home-brew creation of your choice.

5. It should be noted that the testing was very brief -- less than 20 minutes driving time total. As such, I can't swear that this is the final solution but it sure feels like a major step in the right direction. I thought it was worth sharing.

Schematic:



Discuss.
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  #14  
Old July 13th, 2010, 14:06
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kastein kastein is offline
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Re: 98 aw4 tc lockup switch

awesome! Glad you got it working.

My reasoning on the 100 ohm resistors being good enough (heck, probably even less current draw / more resistance would be fine, but I don't like to push my luck) is based off reverse engineering part of the stock TCU. It appears that as usual, the checking consists of:
* is anything drawing current at all?
* is it not drawing so much current it should be on fire?
* all's fine!

From what I could tell when I pulled the thing apart, they used a Sanken SI-5154 positive-side transistor driver for each solenoid, with some other peripheral components connected. Since the SI-5154 has no actual current measuring in it, just "is current being drawn" combined with feedback from the control pin for fault detection, it follows that unless I completely missed something, it's just looking for some load... any load at all really.

The only reason I threw so many caveats and warnings about this being untested info on there is because I haven't tested it, and I haven't yet fully reverse engineered the board, just gotten a bill of materials and traced the wiring on the top/bottom and checked to see if any wiring was hidden on the middle two layers (which I couldn't be sure of.)

I have picked up a set of connectors I can use to build a test/breakout board to go between the TCU and the transmission as of this morning though, and the only other project on the plate for tonight is installing a dryer for my landlord, so hopefully I'll have more solid info soon.
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My yard looks like Sanford & Sons.
Please do not PM me about the AW4 info thread unless you have a truly unique question that is not covered by it or info to add. I do not respond to questions answered by the thread.
Definitely do not hunt down my phone number at 3AM, text me about it, and then threaten violence when I am not helpful. It will not get you what you want.
CTeunuch: Sometimes I really wonder if this sport makes you insane, or it just attracts the mentally unstable.
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  #15  
Old July 13th, 2010, 14:11
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raneil raneil is offline
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Re: 98 aw4 tc lockup switch

Quote:
Originally Posted by kastein View Post
My reasoning on the 100 ohm resistors being good enough (heck, probably even less current draw / more resistance would be fine, but I don't like to push my luck) is based off reverse engineering part of the stock TCU. It appears that as usual, the checking consists of:
* is anything drawing current at all?
* is it not drawing so much current it should be on fire?
* all's fine!

From what I could tell when I pulled the thing apart, they used a Sanken SI-5154 positive-side transistor driver for each solenoid, with some other peripheral components connected. Since the SI-5154 has no actual current measuring in it, just "is current being drawn" combined with feedback from the control pin for fault detection, it follows that unless I completely missed something, it's just looking for some load... any load at all really.
I see. I know nothing of the 5154. Care to hazard a guess as to the minimum current draw that will reliably trigger "yes, it's on!" state?
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