PO 743 test results
#1
Member
Thread Starter
PO 743 test results
Hi all,
I'm working on my sons 1998 Cherokee, 4.0, at, 4x4.
I could use some advise on my next step.
I ran the specific resistance checks and specific voltage tests that I found in a old post from CCKen.
I ran the tests at the TCM plug. The tps and iss and oss sensors tested within specs.
The only thing that tested out of specs is terminal 11 which showed 0 ohms. (Term 12 & 13 both had around 13 ohms)
Does this mean that the lock up converter solenoid is definitely bad? Or are there other tests I should do before replacing the solenoid?
I have done a visual inspection of the wiring where possible and don’t see any other problems
If a new solenoid is needed, Where is the best place to buy new solenoids? I see quite a few listed online with quite a difference in price.
all help is greatly appreciated.
thanks,
Joe Walters
I'm working on my sons 1998 Cherokee, 4.0, at, 4x4.
I could use some advise on my next step.
I ran the specific resistance checks and specific voltage tests that I found in a old post from CCKen.
I ran the tests at the TCM plug. The tps and iss and oss sensors tested within specs.
The only thing that tested out of specs is terminal 11 which showed 0 ohms. (Term 12 & 13 both had around 13 ohms)
Does this mean that the lock up converter solenoid is definitely bad? Or are there other tests I should do before replacing the solenoid?
I have done a visual inspection of the wiring where possible and don’t see any other problems
If a new solenoid is needed, Where is the best place to buy new solenoids? I see quite a few listed online with quite a difference in price.
all help is greatly appreciated.
thanks,
Joe Walters
Last edited by Oldsrip; 01-04-2020 at 10:04 AM.
#2
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Join Date: Dec 2017
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Year: 1989
Model: Comanche (MJ)
Engine: 4.0
Check the resistance at the plug on the firewall and inspect the wiring up to the trans. I think you're pulling the pan and valve body to replace the solenoid though. It's possible the connector came off the solenoid and is touching the valve body, but even if that's the case you might as well replace them all while you're there. Amazon has the set of 3 solenoids for around $60 from various vendors, for example . There is a set that includes a pan gasket and "filter" for an extra $15. The filter is really just a mesh screen which you can hose out with a little solvent. I haven't really seen much a difference in quality between the brand names.
#3
Member
Thread Starter
Thanks for the reply lawsoncl,
I have done a visual inspection of the wiring. Didn’t see anything obvious.
I didn’t check resistance at the firewall plug. I will do that.
I ordered the solenoids yesterday. The same ones you linked to. The price was right and the reviews were good.
It would be great if I pulled the pan and found the wire fell off and laying against the case as you say.
thanks for your help
I will look into it later in the week when the new parts arrive.
thanks again
Joe Walters
I have done a visual inspection of the wiring. Didn’t see anything obvious.
I didn’t check resistance at the firewall plug. I will do that.
I ordered the solenoids yesterday. The same ones you linked to. The price was right and the reviews were good.
It would be great if I pulled the pan and found the wire fell off and laying against the case as you say.
thanks for your help
I will look into it later in the week when the new parts arrive.
thanks again
Joe Walters
Last edited by Oldsrip; 01-05-2020 at 07:32 PM.
#4
Member
Thread Starter
Update on code PO 743
Replacing the 3 transmission solenoids fixed the problem.(Only the 1 for the converter was bad)
The torque converter is now working properly, and the check engine light is saying off after 150 miles or so.
Also replace the filter.
The hardest part of the job is separating the dipstick tube.
My small butane torch wouldn’t get it hot enough. I ended up pulling the pan and tube out together.
I used the oxy/lp torch on the bench and it worked fine. Cleaned it up and replaced oring and lubed it up, reinstalled pan and installed the dipstick tube from the top by pushing down by hand.
The 3 bolts at the rear of the pan are a pain to get started. It would be much easier if the crossmember was notched.
Probably not as bad if you have a lift.
Replacing the 3 transmission solenoids fixed the problem.(Only the 1 for the converter was bad)
The torque converter is now working properly, and the check engine light is saying off after 150 miles or so.
Also replace the filter.
The hardest part of the job is separating the dipstick tube.
My small butane torch wouldn’t get it hot enough. I ended up pulling the pan and tube out together.
I used the oxy/lp torch on the bench and it worked fine. Cleaned it up and replaced oring and lubed it up, reinstalled pan and installed the dipstick tube from the top by pushing down by hand.
The 3 bolts at the rear of the pan are a pain to get started. It would be much easier if the crossmember was notched.
Probably not as bad if you have a lift.
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craiso (01-11-2020)
#5
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Year: 1989
Model: Comanche (MJ)
Engine: 4.0
Thanks for the follow up. Glad to hear it went well. I probably should have mentioned to unbolt the whole dipstick tube as it usually gets stuck. I usually remember to warn again overtorquing the pan bolts as they strip fairly easily.
#6
Member
Thread Starter
Lawsoncl,
I knew going in that the dipstick tubes can be a problem.
And no problems with the pan bolts, I know to take it easy on that kind of thing.
Thank again for your advise
Joe W
I knew going in that the dipstick tubes can be a problem.
And no problems with the pan bolts, I know to take it easy on that kind of thing.
Thank again for your advise
Joe W
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