If the battery is now reading 12.2 Volts after a short time frame I would begin to suspect it. Full charge on a fresh battery should be around 12.7.

Did they conduct a load test on the battery?

 

I've checked and rechecked the TCCM (i know its working bc when I unplug different connectors, more lights show up on the dash. Then when I reconnect it, they are gone)

How do I go about checking the grounding for the vehicle? That seems like it could be the culprit as its something I have not even looked or checked at all.

I didn't get any information about the battery, but I am leaving it on a trickle charge all tonight just to see where it will be tomorrow.

As for the passenger side, there seems to be no corrosion or disconnected wires. I checked up the pillar and under the carpet to no avail of any wires that seemed problematic.

 

Also, since we know there is some communication problem between the ECU and the PCM, what modules would I be looking for to be causing this problem? I have no electrical background whatsoever, so this has been a huge learning process for me. No better way to learn than actual experience I guess!

 

Not to say that your battery is necessarily in good shape, but I don't think that is the root of the issue here(if you get the temp gauge to function correctly, and then have faults while starting, or a slow/lack of crank, maybe check there then)

The PCM is located further back, behind the TCCM, visually check its connectors the same way as with the TCCM, do the same for the black connector that sits below the TCCM(it will have a few Yellow/Black and Yellow/Brown wires in it)

For checking power/ground to the PCM start by checking power at the main fuses for it, #13 and 27, both in the fuse box under the hood, check with battery hooked up, and key on. If good, check the same feeds at the PCM connector, again, key on, battery hooked up, they will be pin 4 & 54 of the smaller connector. Then disconnect battery, and check resistance to ground at pins 1-5, again on the smaller connector. With the ground, even if they ohm out good, I would physically check them, same attachment point for all, located behind the RF wheel well liner, a few inches from grommet they come through.

Also, check and even swap the main relay, top left(when looking at the underhood fuse box) of the large relays.

 

Just went back out there and took apart the TCCM and the PCM. Everything looked great but cleaned it up anyways.

Only problem I ran into was I was not able to connect the battery while simultaneously working on the PCM. It seemed very difficult to remove from its plastic housing and I didn't want to damage anything.

Also, switched the relays (checked the resistance too while they were off).

I'm at a complete loss here. What could be faulty between the two, that I have not covered, to make a loss of communication? The car still allows me to put the key in, all lights work, radio, etc. But when I turn the key, nothing happens except for the "one-click" relay sound from the passenger side. The large F is still there and the AMBER PARK BRAKE light and the ETC/DSC AMBER warning sign are still light.

All the warning messages are still there too. The only thing is, I can use my Parking Break just perfectly. So this has to be some electrical gremlin...

Everyone has helped so much, and I really do appreciate it. The very last thing i'm going to do is look at how everything is grounded and maybe find something. If not, i'll bite the bullet and take her in for repair.

 

So, I don't want to try make what very well might be a complicated problem overly simple, but I'm a big believer in Occam's Razor. If you step back through exactly what you did before this issue popped up, are you saying that you washed the car, cleaned the throttle body and MAF, took it out for a test drive and everything was fine? Then, you popped the hood, removed fuse 26E (did not start the car) and did not touch any other fuses, then came back in the morning, reinserted the fuse, and tried to start it up? At that time, you got the christmas tree dash board?

Do you think the loss in communication (High Speed CAN failure) could simply be the result of a bad fuse? I know you said that you inspected all of them, but sometimes, they may look good while still not functioning correctly. Does anybody know if there is a particular fuse that might cause this? Have you checked the glove box fuses as well as the under hood fuses? Just trying not to overlook the simple things...

 

Also, I agree that I really don't think it's a battery or ground issue, though I would give more credence to the grounding theory than the battery one. However, I think one easy way to check both of these items would be to simply try to jump start the LR3 from another running car. As long as you attach the negative battery cable to the chassis or some other good ground point on the LR3 (which you should always do anyway), it should take the battery and the battery grounding cable out of the loop. Not to say that there couldn't be a grounding issue elsewhere (like to one of the computer modules), but this would at least let you check the negative battery cable and the battery itself off your list.

Too bad you can't push start an automatic... otherwise, it would be an easy test to cross the bad starter theory off as well.

 

cmb6s, I am firm believer in Occam's Razor too. What you stated is what I did before I got the christmas tree.

So today, I went through all of the electrical wiring again... I even removed every fuse under the hood and replaced them with brand new ones just in case that was the issue. It has to be sheer coincidence that I pulled that fuse and then got the christmas tree lights on the dash.

I took a tester, and after meticulously changing every fuse, and even went back to make sure they were working while the key was in the ignition and the battery connected. '

Does anyone know of a way to get the LR3 raised so I can get a better look at the bottom for possibly corroded wires? I can't jack it up with the suspension lowered now that it has been multiple days without it working.

 

I missed the 'removed 26e' part...

Fuse 27, directly underneath that one, is the battery supply for the PCM, and early on these BJBs had issues with the pins being loose, and dropping down to where the fuse didn't actually make contact.

Seeing as how you weren't able to check power to the PCM(which you can do by either removing the PCM, or having the connector disconnected from the PCM) double check that both pins for 27 are seated in the fuse box correctly, and the fuse is actually getting into the pin.

 

What kind of jack do you have? Will the factory LR jack fit underneath and allow you to jack a wheel high enough to get a real jack under the frame? I don't think there's any way to raise the air suspension without the engine running...