SheilaGang

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1st Time Post-er,

Having some trouble with my 2005 TJ, Automatic 4.0L. 66k miles on her, and has been running great until recently...

Driving home one afternoon, cruising at 45 mph (2200RPM), all of sudden RPMs jump to 3000 and the ol' money indicator lamp turns on. She limps home, and that's when I go down the rabbit hole of chasing ghosts and throwing money at her. DYI weekend type of repairs.

Do a full transmission flush and change. She rode smooth for about 10 minuets, back to limping home at 3000 RPM. Took her up to the dealership, read my codes, said I need to replace my O2 sensors. Replaced all four sensors, she rode well for about 15 minutes.

Bought my own code reader, and started my journey of chasing ghosts and blowing cash on my 05 TJ. Got home, needed to re-park really quick, threw her in reverse and headed up my uphill driveway and the transmission slipped while in reverse. Fuming, I plugged in the code reader and thought I was going to explode haha.

Codes that popped-
P0888- TCM Power Relay Sense Circuit
P0562- Battery Voltage Low
P0736- Reverse Incorrect Ratio
P0613- Transmission Control Module Processor
P0700- Transmission Malfunction Present
P1603- PCM Internal Dual Port RAM Communication Failure
P1604- PCM Internal RAM Read / Write Integrity
P0031- Oxygen Sensor 1/1 Heater Circuit Low
P0037- Oxygen Sensor 1/2 Heater Circuit Low
P0051- Oxygen Sensor 2/1 Heater Circuit Low
P0052- Oxygen Sensor 2/2 Heater Circuit Low

I was floored when I read all of these codes, especially after taking her up to the dealership and the only thing recommended to me 3 days prior was all new O2 sensors. Nothing else. At this point I took dove into the TJ threads, and found some small fixes to ease up on some of these codes.

Replaced these items-
Throttle Position Sensor
Transmission Input Speed Sensor
Vehicle Speed Sensor
O2 Sensors x4
Transmission Relay
All fuzes
New Battery
Battery Resistor Pack *AC Knob went out*

My first thought it a bad PCM, triggering more issues and creating more codes. At my wits end on this one, looking for some feedback (good, bad, ugly)!

Thank you for reading. Let me know if you need any information.
 
Being that you have an '05 with an automatic; the trans controller is incorporated into the ECU. The ECU is a known problem which can throw a lot of codes when it goes bad.
Contact @Wranglerfix who is a forum member that repairs ECU problems; to clarify the problems you are having.
In the interim... check the (4) 32 pin harness connectors, the pins and clips for greyish oxidation that can interrupt communications to and from the ECU to the transmission and sensors. Then check the harness connector at the transmission for rubbed thru wiring or dirty connections.
There is also a wiring harness behind the valve cover that is routed around a threaded head stud on the drivers side where the split wire loom and wiring insulation can rub thru shorting out signals to and from the ECU.
 
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Of course, also check that you have a solid ground connection from ECU to chassis, and engine to chassis.

If you have a multimeter you can check resistance on the ECU ground pin to engine and chassis.

But p1603 and p1604 seem to be pretty telling of a ECU issue.
 
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