Thanks, Ken. Couple things before I drop the pan.

How do I check the solenoids at the TCA connector near the dipstick tube? pin cavs 2, 3, & 4 to ground?

Have read not to buy the solenoids from Advance/AutoZone/etc... but rather here Makco or Bulk part : http://www.bulkpart.com/2/product/A3...id/97420K.html
or here: http://www.makcotransmissionparts.com/97420K.html
Are these the "good ones?"

 

Here's the TCA connector pinout to check the solenoids. Use the engine (G102) for a meter ground.

Edit: I don't know if this connector pinout is going to the trans or to the TCM. Go by the wire colors to confirm pin locations. Pic of G102 below and in post #15.



I can't attest to the quality of those solenoids but have seen a write up on NAXJA where A340 solenoids were used. Ebay has them as well as that vendor you linked.

 

the NSS wasn't bypassed by the previous owner was it?

 

I'm fairly certain he did not. It only starts in P or N, reverse lights work, and occasionally (twice in 4 months) have to wiggle the shifter to start it... what would be a telltale sign?

 

After a drive where I had no lock-up, while still warm, checked the solenoids from the TCA connector pins. A and B solenoids checked 16.9 and 17.9 ohms. C solenoid was no reading, or open. I checked them the next day when cold, similar readings for A&B, but C measured 22 ohms. If I clear the CEL, it'll come back after about 15 minutes of driving and won't lock-up... One other check I did was http://www.naxja.org/forum/showpost....00&postcount=4. Before it got too warm and wouldn't lock-up, I verified it unlocked when tapping the brake pedal.
So planning on dropping the pan and checking the solenoids directly and likely replace all 3. Ordered the Makco parts from link above.

 

Aren't those readings alot different than what you got at the TCM connector?

You may want to check the TCA wiring at/near the dipstick for chafing/damage. You may have moved the wiring around a bit when taking the readings from the TCA connector which may have changed any chafing.

It wouldn't be the first time wiring was found chafed near the dipstick.

 

My check engine light is off! hopefully for good...

Dropped the pan, fortunately didn't have to fight the dipstick tube, it had a joint with a o-ring. Checked all 3 solenoids directly with my new $20 autoranging multi-meter. Lock-up showed 16.7 ohms. Other 2 were 14.5 and 12.5. So I replaced all three. BTW, the new ones all measured about 12.5 ohms. Replaced the filter/screen. Not too bad a job. The extra wiring on the new solenoids had to be routed and tucked away. Didn't see any debris in the pan, magnets had a tiny bit of fuzz, barely visible. Looks like the pan had been off at least once before, black RTV over the original pink RTV (pink I understand was from the factory).

Refilled with Dex/Merc III and drove it for 30 minutes at 50-60 MPH. Locks-up solid and no CEL! So far so good.

Back to Ken's question on wiring. I have had readings as high as 36 ohms on the lock-up solenoid, the other 2 were around 18 at the TCM. I haven't checked at the TCM since installed the new solenoids, but did measure at the TCA connector, all 3 solenoids measured 14.5 ohms and I measured the meter wiring and it was ~2 ohms, so figure it's good from that point. I'll check at the TCM and let ya know.

Thanks for all the help here on the Cherokee forum! A great resource for what to expect from these beasts!

 

Hopefully the last post on my P0743 code! Have a 100 or so miles on it since replacing the solenoids, and the dash cluster showing no hint of CEL yellow..

I checked the new solenoids resistances at the TCM connectors, pin cavs 11/12/13 to grd (pin cav 23), all around 14.2 to 14.5 ohms, so subtracting a ohm or two for my paperclip/alligator clip/test wiring, I believe I don't have any issues with corroded connections in between. So maybe I'll put all the panels back on! Thanks again Ken and others who've contributed .

 

Thanks for the follow up and I hope it stays fixed.