96 XJ laundry list of trans codes P0743, P0753, P0713,P1763, P1765

[RdWarrior]

Hello all,
First time poster, long time forum lurker. Helping a friend out with his 96 Sport and it's got a bunch of transmission codes I don't even know where to start to troubleshoot.

P0743 Torque Converter Clutch Circuit Electrical
P0753 JEEP - 3-4 Shift Solenoid Relay
P0713 JEEP - Transmission Fluid Temperature Sensor High Input
P1763 JEEP - Governor Pressure Sensor Too High Conditions
P1765 JEEP - Transmission 12V Supply Relay Control Conditions

Where is the transmission relay located?
Transmission seems to be shifting fine, fluid doesn't look or smell burnt, the only thing is, the truck refuses to set readiness for emissions and I am assuming the trans CEL's are having something to do with it.

Is there any exploded diagrams showing where all the sensors are for the AW4, or any guides on diagnosing the TCU/testing to see if it's the culprit? Any help would be GREATLY appreciated. Thanks!

[Agreen]

There are 2 connectors right by the dipstick. Fairly large, about a 2" cube shape. One is gray, one is black. I forget which one is which. One is for the transmission control, the other is for the range sensor (senses park, reverse, etc). Pop them loose and see if it's gotten water in them. Maybe spray some electrical contact cleaner in it too. The other thing I can think of is that the "twisted pair" that sends information via CAN bus to the ECU has an open in the wires somewhere and information is not making its way back to the ECU.

[RCP Phx]

I'm wondering what you are using to pull those codes? Half of them do not even apply to the AW4.

[RdWarrior]

I know! That's what I'm so confused about. I didn't think it had a temp sensor built in it.
I've tried it on a few generic obd2 scanners.
Also the local smog station pulled the same codes when my buddy went to get that taken care of.

[Agreen]

The only 2 that apply to the AW4 are the first 2. What's the part number on the ECU? (It's on the driver's fender by the windshield washer fill)

[lawsoncl]

I'm guessing he has a GRAND Cherokee and not an XJ.

[RdWarrior]

ECU part number is P56041206.

I'll be getting my hands on the truck again Monday and probing TCU harness to check resistance and the usual grounds in the engine bay to see if any of those are missing.

[RdWarrior]

Originally Posted by lawsoncl

I'm guessing he has a GRAND Cherokee and not an XJ.

Nope, definitely an XJ.

[lawsoncl]

Originally Posted by RdWarrior

ECU part number is P56041206.
...
Nope, definitely an XJ.

Google says that part number is for a 1996 Grand Cherokee?

[RdWarrior]

Hah, someone put the wrong ECU in it?

[RdWarrior]

Trust me it, is is an XJ, a very rough 96 Sport. I can obviously tell I've had an 87 Pioneer and a 99 upcountry package'd classic before . Welp, that might be part of the problem.

[RdWarrior]

Anyone know what part number ECU I should track down to put in this ? I wonder if that is why it's popping all these transmission check engine lights.

[Agreen]

Originally Posted by RdWarrior

ECU part number is P56041206.

Yup, that was my suspicion. It's a grand cherokee ecu.

What sucks is that 1996 was a funky transitional year, so the ECU might be a little difficult to get the right one. I don't know for sure (specifically for the ECU) but I do know that 96's are known to have parts from a couple (maybe 3) years of xj.

[RCP Phx]

Here's the ecu for a '96, I have purchased 2 from these guys.
https://www.fs1inc.com/1996-jeep-cherokee-engine-computer-pcm-ecm-ecu-programmed.html?gclid=CjwKCAiAjp6BBhAIEiwAkO9WumJp cx1vuYtHX_Pb6hSNmxMSoSTa0_7kxJ5rzuEE8EJ0_odtYOALCR oCJxYQAvD_BwE

[lawsoncl]

Originally Posted by RdWarrior

Anyone know what part number ECU I should track down to put in this ? I wonder if that is why it's popping all these transmission check engine lights.

Yup. I'm pretty sure the 96 Grand manages the trans with the ECM instead of a separate trans computer like the XJ. So the Grand ECU is likely bitching because it doesn't see the transmission solenoids or sensors connected.