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Code PO700, PO743 1998 cherokee

M

moneypit_k5

NAXJA Forum User
Location
pdx
98, 4.0, AW4...

Ive been chasing engine light codes, finally only have two left.

I understand PO743 to be a shift solenoid. Ive checked the wiring, Ive replaced the lockup solenoid, sure wish I would have done the others then.

Is there a source for buying just the two shift solenoids in a kit?
I sure hate to buy a new lockup solenoid since i just did it.
 
the input and output speed sensors? I would junkyard them. You can pull them off any 98-01 AW4.
 
kastein said:
the input and output speed sensors? I would junkyard them. You can pull them off any 98-01 AW4.
Click to expand...


I beleive thats which ones they are. if im not mistaken, PO743 has to do with the solenoids inside the pan right?

THere isnt a junkyard within 100 miles that has a 98-01 XJ in it.
 
I think we got sensors and solenoids mixed up somewhere along the line. The P0743 is the torque converter lockup solenoid (aka solenoid #3 or solenoid C depending on what service manual you're looking at).

There are 3 solenoids, and I would test all three using the guide at http://www.transonline.com/transdigest/magazines/1997-10/Shift%20Pointers/index.html before you get too far. Verify that its not a problem with the wiring to the tranny as well.
 
oh, you said "two sensors" in the second post and confused me, sorry.

You can buy solenoids individually I think, but definitely measure them when they fail and see if they're within spec, 11-15 ohms.
 
Sorry, I meant solenoids. I ohmed both of the shift solinoids as well as the old TC solinoid. All three were within spec at 13.2 ohms. I went ahead and replaced them anyway since I had the parts.

So I am still getting a PO743 code. Something that I find odd, the jeep has a very erratic idle. jumping around anywhere from 2k rpms to dying. it seems like it began doing this when I replaced the TC solenoid initially.

my NSS has been acting up a little bit recently, could that have anything to do with my problems?
 
I was getting the same two codes on my 98. I checked resistance and the solenoids were all in spec, and I had just replaced my NSS recently (broke the old one getting it off). My tranny fluid was quite bad. I did the whole drain the pan, refill and drive a couple hundred miles, drain, refill, repeat thing. I did it four times, replaced the filter the last time and no more codes. When I was getting the codes my tc wasn't locking up, after it was working fine. Hope it is something that simple for you.
 
I was hoping the same thing when it first started giving me trouble. So far, Ive drained 3 times, done a filter once. The thing is, my tranny doesn't act up at all, and never has. it shifts perfectly, and locks up perfectly.
 
Did any of you guys check out your TPS(Throttle Position Sensor?). I've heard when they go bad they can cause transmission shifting problems. Also did you guys try unplugging your TCU and manually shifting to see how it shifts? My buddy has a 98 and it only shifts from 1-3, but the TC does lock up.
 
praetorian said:
Did any of you guys check out your TPS(Throttle Position Sensor?). I've heard when they go bad they can cause transmission shifting problems. Also did you guys try unplugging your TCU and manually shifting to see how it shifts? My buddy has a 98 and it only shifts from 1-3, but the TC does lock up.
Click to expand...


Ive considered my TPS as a culprit as well. This jeep has a new one on it, but that doesnt mean much. anyone have a quick test procedure?

Ive unplugged the tcu, doesn't change anything.
this jeep really doesn't have any shifting issues. i wouldn't even think there was a problem if the light wasn't on.
 
so, last night I was playing around with the harness under the hood, I unplugged the new TPS and the jeeps idle went into closed loop, smoothing right out. I put another TPS on, and it runs and idles great. it didnt do anything for my PO700 and PO743 though.
 
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