jeep58

Checked again battery is good charging is good jeep starts right up, so I disconnect battery and now everything is good. After sitting for a couple days it will go back to check gauges, just rambling now with this problem!

Noah911

Okay, lets see? Frustrated?

We know something. The door modules ALONE are not the sole reason, if reason at all, now that they are unplugged. Sounds like other than your check guages, check engine, and your brake warning light being on, its all working correctly again. Albeit, having now unplugged and disconnected both the door modules right? Your battery and main charging and cables appear in working order too. Your charging is better than mine.. Mine was 13.65 and 13.58 no load and fully loaded respectively done today. Original 22 year old alternator and 22 year old factory terminals. Going to take those terminals off to replace with new pronto! Refresh & retest...

let me not pretend.. To be clear. This is a quagmire. It can end up having been super simple thing, but it is in a super complicated to fully understand communications system developed by DCC to suit 1998 data-reader scan tool universalization efforts...

In case you wanted to know a little bit more. I went to the horses mouth for it for you. I'm interested in it. To be clear, I never really knew what much of this was until I started helping you. I knew of it... I think yours is getting complicated enough to think of real high quality expert work - testing the PCI bus module(s) computer PCM and BCM problems, and all the other 32??? other modules while they are at it. That would be okay. Just because you don't have the high dollar, all the right tools like this, doesn't mean you couldn't of gotten to it! Still can too... I fully believe, if it goes to acting all totally crazy again in the near future, that PCI bus pin #2 just needs to throw you a bone! Get to pulling off modules... It was already measured by you once, and it was abnormally high in the 3V+ (normal-high = 2.5V upper limit) once recently. There is other things to do. You have to look for shorts and opens between systems, wires, connectors, modules... We can do all that with a multimeter. Anyone would have to do this anyway, even with after data reader results, and/or expert decisions. Below is copy and paste about what I said:

Did you know when connecting a scan tool to a DaimlerChrysler vehicle that the scan tool links into a network of up to 32 modules? Like most manufacturers, DaimlerChrysler uses a communication bus to allow different modules to share information. Diagnosing transmission problems require the integrity of the communication bus primarily because the scan tool utilizes the bus to accomplish all of its diagnostic tasks. When receiving a "no response from transmission controller" message, diagnosis of the communications bus is necessary before diagnosis of the transmission concern. DaimlerChrysler is currently using two types of module communications: Chrysler Collision Detection (CCD) and Programmable Communications Interface (PCI). The CCD bus system was introduced in 1988 and is currently found only on Ram truck and van models. The PCI system, introduced in 1998, is found on most current DaimlerChrysler vehicles. The following chart identifies the type of communication system found on DaimlerChrysler vehicles.

Skipping the charts. They show multiple layouts and different configurations.. And just enough more pertinent info for you. It's great! Its pulled from a rather thick document all this info.

PCI Diagnosis: The PCI bus will experience complete failure when the bus is shorted to ground or the bus is shorted to battery . Unlike CCD, each module has the ability to control the voltage on the bus. If one module fails or if a module's PCI bus circuit opens, the PCI bus does not completely fail. The PCI bus will not recognize the effected module, but all of the other modules should still be able to communicate successfully. This is a good fact to know when diagnosing a "no response from controller" problem. Try accessing different modules to determine if the bus failure includes more than one module. If the scan tool cannot communicate with any module, either the PCI line to the DLC is open or shorted, or the bus has experienced complete failure (short to power/ground). If the scan tool can communicate with other modules, the failure is either an open in the bus circuit to the effected module or the module itself. Vehicles with PCI contain a "hub" where all of the different modules join their PCI wires. On some vehicles, the hub is the Body Control Module (BCM) or the hub might be a simple "diagnostic port adapter", which is used on Jeep Grand Cherokees.
end copy & paste

Even if you go to have to turn for help if decide thats best, you will walk in maybe knowing a little better wtf you are talking about at least.

Noah911

BCM kills your guages. The one click back ignition turn of the key energizes the lights, radio, fan, windows (you say your windows work when the ignition switch is turned to the acc position even when having the major issues when and with running), you know the accessories... When you turn the key to the run position, it energizes the ECM-PCM. Turn it more forward to start, it energize the starter/ignition circuitry here in this position. So, the key turned backwards into acc position and everything is fine? If you turn the key forward into the run/driving.. When the ECM-PCM, which includes the BCM.. when they energize, that is when it expresses extra problems? But not in acc?

jeep58

Yes I will check to see when the check gauge light comes on to see if the accessories work. I disconnected the cable that went to the block and cleaned it up real good with carb cleaner oil grease coated the bolts on the block. After I started the jeep the check gauge light was on but the tachometer was working before everything would not work. Whatever is causing the problem seems to happen when the jeep sits for a period of time almost like a capacitor is discharging. I will check tomorrow start it up and see if it does the same ( tach working and check gauges light up) if so I am getting closer to resolving this problem thanks for the information on how the BCM works!

Noah911

Of course. You are welcome. The info some of it is coming from a 187 page document produced by - FCA Fiat Chrysler Automobile, The Performance Institute. It is from their official manual dedicated strictly to the bus. I downloaded the whole thing... I trust the source.

It does get real complicated in a hurry. There is a lotta lot of information. Your BCM is actually programmed with a registry and the build option configuration specific to your vehicle model. There is a back-up condensed storage of this same information being stored on one of the other less dominant modules for in case if the BCM fails to the point of interfering with scanning.. Also, for when replacing a BCM you must consider this because if not programmed with this data correctly, it can cause confusion among the PCI bus system, and it could result in the appearance of falsely corrupted modules.

The fundamental way modules communicate is through voltage pulses. Modules are capable of both transmitting and receiving voltage pulses. The module on a communication network is exposed to every signal sent by all the other modules, but can sort out which signals to use and which to disregard. Each module on the network monitors for a fault. If a fault occurs with a particular input or output, the module that is hard-wired to that particular device
may be designed to detect it and set a diagnostic trouble code (DTC) as a result. Your SKIM module... It's soo confusing to try and really understand it, but since your guages don't work and the SKIM lights up.. Then, this means both of these two things that are appearing as malfunctioned.. They are fine.

Hear me out here.. Since it is starting and it is running with the SKIM light on, it is not your SKIM module. It is most likely this SKIM module is just sending a defaulted NO RUN signal, since the Jeep does run. Same goes for with your cluster.. Its fine. The faulty NO RUN coming from SKIM may get extra upset to actually result in... A NO RUN condition periodically still though..

They are hard-hard-wired in, and notifying you that they detect a problem. Often, it is a short somewhere with/to a module. Or, I have heard it being from corrosion and water seeping into wire insulation, boots, and connectors...

Noah911

I am just throwing a case.. Not of entire similarity to your problem;

Vehicle: 1999-2004 (WJ) Jeep Grand Cherokee

Concern: All 4 power windows inoperative.

Cause: The BCM (body control module) is electrically "locked up".

Resolution: Disconnect the battery for about 10 minutes. Reconnect and retest for proper operation. This should reset the BCM.

Details: Diagnosis with a scan tool should be the first step in a case such as this. A module scan with a DRBIII scan tool would have indicated that all modules were functional except the BCM. If disconnecting the battery does not resolve the issue, further diagnosis will be necessary.
(end)

You know,
You can plug in any obd2 scan tool (Advance AutoZone) that has live data display, and view the input/output readings of the PCM to see if it is active. If it's an intermittent problem you may have to time this testing for when having the bad symptoms. Good info to have.

Although being complicated, an OBDII, or even a DRBIII professional reader tool. The OBDII in particular will be limited here.. It may just simply show a "no response from pcm" message related to a short. An off-the-wall example would be a shorted out CPK sensor disturbing the bus, and pcm appears 'off-line', because it is. It is off-line due to the CPK sensor shorting out...

This is dicey.. And I do not fully recommend doing this until you have searched out many other avenues well enough first. With you having a remanufactured pcm already, it makes some sense? A bad pcm can truly cause ANY problem imaginable to occur. There is only 4 screws holding it together (and hopefully.. some sort of water moisture sealant they used), and you can unscrew it to look. You will surely notice signs of any corrosion located inside of here, if it is present. Also, if internally shorted, possibly due to moisture, you will surely see signs of it having burnt-marked its internally shorted location, and maybe even some melting... I would get all of the electrical and fuse box etc connections cleaned up and inspected first. First, also check at the correct pins located on the PCM, its fore-aft wiring, and the correct pcm groundings too.. For properness, before opening up a PCM.

(edited to add):
I seriously with the amount of possibilities present, could write attempting to explain in-numerous scenarios and reasons for such and such... I don't want to confuse anyone. Or, myself. Tell me to stop if necessary.

What can cause a major PCM internal failure to happen outside of moisture? An ignition coil has some real power. It is obviously connected up to the PCM electrically. That having a problem, such as shorting out in different ways, it would be able to mess up a PCM pretty badly. Of course, there are no other expected symptoms matching for your particular case with this though, to even think this...

jeep58

I checked the battery although it starts car and is less than a year old it reads 12.4 volts with meter surface charge, I am going to return the battery and get a new one( free return up to a year). Is it remotely possible that check gauge light comes on after a few days tied in battery?

jeep58

Ok so checking with battery chart 12.4 is about 75 percent charged so battery is ok !

jeep58

Still question will weak battery cause check gauge light to come on ?

Noah911

A car battery is considered fully charged at 12.6 volts or higher. ... Though not fully charged, a car battery is considered charged at 12.4 volts or higher. It is considered discharged at 12.39 volts or less. Note: A fully charged specific gravity of 1.265 corrected to 80°F is assumed.

mine is 12.8V at no load. Yours is borderline low. An internal cell type of other issue could be present, but I would doubt it..

A battery at 12.4 or lower at 12.3 would be very highly unlikely to be the sole cause, or cause any at all for a check engine, or any other light.

jeep58

Thanks Its a walmart battery return within a year free replacement so I will return. I saw you new jeep beautiful looking I had that model before the one I have now, I like that model better than the Wj !

Noah911

Thanks! I am still getting to know it better yet. I'm going to put it through its paces real soon. I hope it is as good as I think it is because I have plans for it. I want to bias it more towards the off-road side once it has proven itself solid to me.

I like them both a ton! The ZJ is still new to me, so I am really enjoying being able to work on it getting it into shape, and driving it. It needs a better radio and speakers compared to my WJ. The ZJ feels lighter and more peppy to me. I think they are good vehicles!

jeep58

I cleaned the grounds and installed new battery only light on was brake light had mechanic bleed brakes and now that light is out. Ok so everything is working no more check engine gauge light on, only problem is that the scan reader is saying possible malfunction with emission, mechanic said to drive it 60 miles that the new battery has to rest itself with the electronics, Drove jeep appox 40 miles and still get that message it is the Autel Auto link scanner model AL319 the yellow triangle icon lights up "possible malfunction with emissions" No codes pending or stored, I just want to get the jeep inspected. Any suggestions?

Noah911

It's just emissions.. Is there a number associated with the 'possible' problem with emissions message you got from the reader?

It's normal at very first to get an idle that stumbles and stalls out sometimes, when replacing a battery if it got really low, or if it was actually dead for a time. The computer has to re-learn its automatic settings and all of the sensor inputs sometimes after the battery is upset, or just disconnected. This process of re-learning and re-setting may disrupt the emissions system. It is supposed to, and should eventually dissapear.

jeep58

Thanks Noah !!!!!