There’s a guy in Florida that started a business called Wranglerfix. He builds PCMs for 05 and 06 TJ’s.

 

He's actually manufacturing new PCMs?

 

had the 4 bad O2 codes - resolved. - 2006 wrangler unlimited rubicon with 4 liter 6 cyl
first weird thing is my jeep has only 2 sensors, not 4. So I immediately suspected things other than the sensors.
checked wiring for shorts or melting from exhaust, no probs
checked for clooged cat - showed no signs so told myself thats not it
looked for bad fuse or relay, even moved ADC relay into horn position and tested fine
wanted to check everything before contemplating re-soldering the PCM connectors - was not looking forward to trying that unless last ditch effort
noticed that the cable connection closest to driver side slid in and out with ease, the other 2 were very difficult to remove. McGiver'd a solution to press on all 3 connectors - no code for 70 miles so far

 

A guy has to do what a guy has to do.>

I would take it a step further and use a block that only presses on one connector at a time. Just because it looks like the obvious solution doesn't necessarily mean it is.
Good luck

 

Time to join the 05-06 Rubi ranks with O2 errors. My son inherited my wife's 05 LJ Rubi (auto), lives about 1.5 hrs away, and had several inspection issues. I lent him my 04 TJ Rubi back in Dec while I had an extended vacation. The LJ always had one O2 that would throw an error unless we got gas at this one station. We would go there prior to every emissions test. After getting him new tires, replacing brakes at all corners (and filling divots from the pad ears), a water pump that blew suddenly with no weeping, oil leaks, and a few other issues, the LJ suddenly had shifting issues (hard shifting, not shifting till 3000RPM+). I checked the codes (expecting just the one), and had P0031, P0037, P0051, P0057, P0700, and P0562. The alternator tested clean (14.3v DC, diodes good, 0.03 AC), but battery was a hair low and failed the shop test, so I swapped it out. When the P0700 became a permanent MIL, the gears started slipping. Reset codes and tranny went back to hard shifting. I'm hoping the P0700 is a side affect of the power issue. Replaced all O2 sensors (w/o any expectations) and no change. Checked wiring from PCM plug to each O2 plug. Check PCM plug out to PCM plug in. Checked grounds. Checked all non-grounded circuits for shorts to ground. All good.

I sent the PCM to G7 and they said they found no hardware errors, but saw software errors and re-flashed it. I'm a little skeptical about this answer. Plugged it back in and the errors returned. O2 errors where immediately permanent MILs with corresponding pending errors.

I saw a trick online where you cut the connector off an old O2 sensors, plug it into the harness, and connected the heater leads to a head light. When I started the jeep, the expectation was that the heater circuit would turn on the head light. However, it did not. By mistake, I turned the key on, but not to start, and noticed the head light powered on for a brief period. I heard a click from the PDC and tracked it down to the ASD relay. After some research, I found out that the power systems cycles 'on' with the key, but shuts down after around 1.8 second if not started as a safety feature (fuel pump shuts down as well as other items). I was getting 5.2v across the head light pins. So now I know the PCM is able to send power to the O2 heaters when 'on', but not when the jeep is running. I rigged a test where I ran 12v through the PCM plug to the heater circuits, and check the volts on the signal side at the PCM plug. Within a few seconds of power, the O2 signal circuit started registering a voltage. Long story short, all four O2's heated enough (proving the heater worked) to start receiving O2 signals through the other circuits.

I plan to reach out to G7 tomorrow. Since I can't find any PCM schematics, my thought is the P0562 might have something to do with voltage being sent to heater. It can send enough juice when it's not running, but can't when it is. I'd hate to have to replace the PCM after all the horror stories with the TCM, SKIM, etc. We'll have to see where this goes.

 

Seems like an odd error, but hopefully you've narrowed it to the problem. In for the fix.

 

Original poster here. Just saying there is hope. After my nightmare PCM problems and finally having the dealer find and replacing it, my Jeep has been running well and dependable. I actually sold it to my neighbor and can look across a couple acres and see it in the pole barn.

He is delighted to have an 05 Rubicon TJ and one built up like new.

Coming down a tricky fin in the trusty Rubi 2017, Moab UT

 

They are rebuilt, but I’ve talked to him on the phone and he takes great pride in his work. His motivation was the transmission issues with the 05 and 06 TJ’s. I learned about Wrangler Fix via a friend via Blaine.

Their website...
https://wranglerfix.com/

 

Hello nottoday. Maybe your anger insulted the parts person. I just put a new pcm in a 2008. They come blank and the dealer has to program them.

 

Yes the voltage for the O2 heaters run through the PCM. With most vehicles it is a ASD power supply then the PCM controls the heater off and on. It has to run through the PCM so it can be monitored for emissions. We heat the O2's to get them working sooner.
With the JK's the problem was when the ASD relay stuck on it would overheat the board in the PCM and damage it. The vehicle would run fine but would have heater codes for all 4 O2's.
There is no perfect system and the Manufactures are always walking the fine line between cost and durability.

 

Cost was the argument when Morton-Thiokol designed and produced the Space Shuttle Solid Rocket Booster and we know how that faulty design turned out.

Research via Google, replacement 2005/2006 Jeep Wrangler PCM's, you will see that the 05/06 Jeep wrangler have the highest replacement cost because they are in short supply.

My 2005 replacement PSM and install was near $1800 and by the time the dealer was done I had $2200 charge.

Point is the Chrysler PCM design has many more failures than other vehicles. Chrysler, for what ever reason, accepted the design and build and potential failure rate as acceptable. Problem there is they passed on the cost and trouble to those who bought their Jeep while the stock holders gained profit. Thus it shows a low moral code of ethics.

 

Well - two thumbs up for WranglerFix!

 

A long shot but look at tune 150 on Facebook. Wayne is the one I am sending my ECU to for an update.

 

Early JK's have this problem and it usually turns out to be the driver in the pcm. Being that your's is a TJ and the codes went away I would guess that you have a wiring problem. The heater circuits usually get separate feeds from the pcm but If I remember correct they share a ground circuit with a lot of other stuff. I would start with your ground wires, wherever you can find them, fender, firewall, battery. As with older vehicles don't be afraid to run a couple extra grounds. From the frame to the body and engine.

 

Thank you for the info. I'm going to try and diagnosis the problem this weekend. I did have a loose negative battery clamp but I don't think that fixed it. It's running fine now so I'm curious to see what happens as the weather warms up and I put some miles on it. The problem only happened when the outside air temp was hot (80 degree +) and with a heat soaked engine.

 

I don't know how the pcm gets power for the heaters. Your TJ has ignition switched power and relay supplied power. The heaters themselves won't cause it not to run but a power supply problem would. Have a good look at your relays. For the price of them I would change them, or at least move them around. See if the problem changes?

 

I'm not sure if this is helpful but might produce some knowledge if there is an experienced person out there.

I was told that the TJ PCM (computer) had the power to the O2 heaters running through the PCM, the problem with that is that voltage could harm the PCM if there was a short within the black box. Supposedly a design flaw. I don't know if this is correct but I was informed of this by an experienced Chrysler mechanic. He thought that this was causing some of the PCM fails.

The computer design should have activate a relay outside the computer box to initiate the high voltage need to the O2 sensors.

 

Going down this road with my Jeep, replace the cats (much needed) replaced 4 o2 sensors, still threw all 4 o2 sensor codes at the same time, replaced the PCM, passed smog. Now the lockers quit working, I’m hoping this is not a PCM ��Just turned 100k, and yes I have the S on the 8th digit in my vin.

 

Welcome to. ROF Nottoday. You are right about it being difficult. I had two choices though. 1. Walk away from my Jeep or 2. Find a PCM. California won’t smog a vehicle with engine codes. If they see a code, they immediately send you packing. Good PCMs are out there, but not like the 05 and 06’s from WranglerFix.

 

Yes NTK is MOPAR OEM.

I would check the ground straps first clean/replace.

Those codes are resistance related so I would guess grounds but ...since you had one code before you changed sensor and multiple after I would check wiring , things you touched.

Check the sensor you changed make sure those wires didn't get twisted together. Ive pulled a couple out that were connected then screwed in twisting the wiring, one pulled out of a connector. Screw it in then connect it. The connectors are a pain in the ass and pulling on and moving the wires around can crack or pull on wires and connectors

 

SteveV8,
What are ground straps, not familiar with that term.
I did have trouble pulling the sensor connector apart and man handled it. Other than looking at connector is there a way to test with a meter?
If I did screw up the connector that is on the wire bundle how do I replace that? Cut and splice a new one?
Thanks Bob

 

The only time I seen 4 at a time, there was a blown fuse.

 

Yes the heater circuit fuse is an excellent possibility, I was just looking at that. Check fuse in power distribution block on fender its a 15 amp and noted in my fsm as #16 (mines a 2004 FSM)

The relay for the heater circuit is in that box also which is another possibility.

ill look for the ground connection location for you. ground straps are just connections to the engine or components to ensure the ground path for the electrical system. The most prominent easy to see example is the flat strap from firewall to hood.

The ground connections for the harness with he o2s is on the pass side of engine just rear of the distributor/cam shaft module eyelet comes out of harness and attaches to engine block.

 

It's also possible with those miles that you could have issues with your mini cats which are warm up cats. That is the code (0153) that started my head scratching for awhile. I replaced all of the sensors with OEM and then it would only set codes when off road. I drove it all the way to Moab, no codes. First trail, set the code. Finally the guts of one of them let go, looked like a big wad of gum and blocked the exhaust so I had no power. New warm up cats obviously solved the issue.

 

All good information. I'll get right on to checking the sensor plug and fuses.

Just wondering how you can determine if the cats are good. To check the cats do I need to pull off the exhaust pipe and take a look. If the insides of the cats look intact are the cats good?

 

Trying to get the stock 05 Rubicon to pass the smog test

I have read that Jeep on board computers go haywire sometimes and will keep you posted on fixing this problem for the benefit of others.

Problem all 4 O2 sensors code bad after replacing one

Checked the fuses and all seem good. Actual #16 is missing on my Jeep, 05 Rubican. Since I don't have one and no codes before this, guess I don't have to have one.

Looked for a loose ground finding nothing at this point that appears loose or faulty. I'll keep looking though.

O2 electric plugs look OK even though I broke the plastic lock off one, which really pissed me off, it still pushes snug and tight. guess I will have to safty wire to make sure it remains locked tight.

* Got talked into putting in a Mopar O2 sensor from the Jeep Dealer. As noted on the original post I changed the O2 sensor for an O'Reiily NTK. I found a chart that list the O'Reiily as a substitute rather than OEM even though the Mopar one is an NTK too and looks exactly the same it does have a different part number.

So I got to start somewhere even though I am not happy to spend $65 for a new o2 sensor and then replace it with a $85 o2 sensor

Cleared the codes and now driving to get data for the required smog test. If the codes come back the next step is the dealer wants to reflash the PCM.

I'll take words of wisdom from the forum. Thanks Bob

 

What did you find was the problem? I have an 05 also that is doing the same thing. I replaced the pcm, 02 sensors map sensor and speed sensor, and continue to have problems.

 

Some similarities in this thread. Deals with wiring harness I believe.

http://www.rubiconownersforum.com/forums/19-general-tech/70113-2004-2006-pcm-lifetime-warranty.html

I'm looking at it for my 06 which is giving a IM code of not ready. It may be worthwhile to run the test and point this out to dealer they may have forgotten about it or not have checked.

 

I have reoccurring codes p0031,037,051,057, and once in approx. 80-100 miles it throws a p0344. I have replaced all 4 02 sensors with NTK replacements and replaced OPD and cam sensor. code shows its an intermitant signal loss so have looked at grounds and have replaced negative battery cable just to verify a good ground