I think at this point you need something that can give you live voltage readings at the battery. I still very much think you have a voltage issue and with a new battery/alt then neither should be it on their own. You have to have a ground issue, main fuse issue, etc. You also need to pull the battery and check the main ECU connectors for corrosion. I took apart my neighbors truck. We suspect the battery had exploded at some point, there was SOOOO much corrosion that the connectors are now only snug fit, no latches. Anyway, look at all that stuff behind the battery behind the small black panel. Not hard to do, just takes a little time.

 

the saga continues. Definitely need a GAP tool.

• So pulled the battery, took it back to get it tested and they said it was good to go.
• cleaned the terminals and battery connections again.
• pulled the TCM module again and rechecked the plugs, even opened up the case just to make sure, didn't see any corrosion or board issues. the connections actually were really clean inside and out. I use some electrical cleaner on both just in case I missed something.
• Battery was at 12.3v (not hooked to anything), charged it up completely and put everything back together.
• Starts up, running fine, no crazy fan speed, no errors, nothing. let it run for about 5 min, it's reading 13.9v. turn it off, it's 12.7 and drops to about 12.4 before it levels out.
• Start it up again, same, no issues.
• Do this a couple more times, same result. Battery didn't get below 11.3v when starting, tried that a few times.
• let it sit, closed the hood, go to start it again, starts up, low tire light pops up.
• Still running, i'm outside the car, the hazards go off. Get in the car, the door locks cycle.
• Turn it off, turn it back on, still starts, more lights, now the TPMS error, and the radio "vehicle fault, system shutting down" on the radio, that cycled though.
• Turned it off, plugged in my basic code reader, no codes.
• Start it again, more errors, HDC, TPMS, Parking Brake, etc. Still started up.
• Tried one more time and finally killed it. Got the U0167 code, nothing else, which is what I was getting.
• Battery was down to 12.2v, took it off and it's just sitting like a driveway ornament now.

Gonna mess with it tomorrow, see if I can replicate what happened. Looks like something is really sucking the battery dry when it's not running. Seems that sitting for at least 24 clears all the codes and will let it start up. Cleaning the TCM seems like it was coincidence since it hadn't been hooked up to a battery in 2 days. I also replaced the brake switch before all this, so I have an extra, it's cheap enough that I now have a backup.

I guess this is better than a car payment...

 

Well obviously you are killing the battery average with that many starts in a short time, thats is a given. But we need running voltages at all those times, you only gave one reading of 13.9, which is not bad but also a slightly low for a cold start.

 

Stayed at 13.9v. Checked that a few times while it was running. i'm going to go through this whole thing again tomorrow, after charging it.

 

Thats a touch low and not typical, it should increase/decrease. Did you check the main fuse near the positive post? Did you go over your grounds and clean them? It still very much acting like a power issue. Was the replacement alternator a proper one or some inexpensive unknown? Some here just replaced their alt to find the alt was also bad, third one was good. I even had a replacement for my BMW that was bad, again third was good. So never rule out new parts.

Alternatively, it could be a connection on the central junction box, CJB, behind the glove box. If its been touched, it could be a connector that is not seated right. Or if you have wet carpets, it could be water damage of the CJB.

 

Hey Wtrdog... I have the EXACT same saga going on with my (new to me) 2007 LR3 HSE 4.4L., 105k miles.

I did have mild corrosion on the Transfer Case Module connectors. Like you, the inside was surprisingly pristine. I cleaned both sides very well. All good for three short drives, then while idling in the driveway the HDC, TPMS, PARK, door locks actuating etc., again.

So then I went after my other known electrical problem...previously repaired rodent damage. This actually fixed my Left Headlight Comm error.

Took several more drives. All good, but the IPC was still showing communication errors with TPMS and Parking Assist. Previously it was showing comm errors with the Park Brake module and TCM. I was considering living with these comm errors, but it flipped out again while idling in the driveway.

I use an Autel MS906BT scan tool which gives a real-time voltage read in the upper-right of the screen which remains normal. The battery is new-ish, the alternator looks original.
I'll keep digging. I hope you do too!

 

I’m having identical behavior. I’m focusing now on the Instrument Cluster as the source of the problem.

Good battery, good alternator, cleaned the Transfer Case Module contacts, inside TCM checked pristine, and repaired a few ground wires in the engine compartment.

I saw a few posts on same problems where Instrument Cluster or repair fixed this. One post described the Trip Meter Reset button as the “self destruct button.” I tested mine and successfully triggered the self-destruct sequence. Another post mentioned ClusterFix.net as a repair option. I think I’ll give that a shot.

 

I sent my cluster in for repair yesterday. I'll report here when I get it back. If you try to start with the cluster unplugged, you can mimic the flashers, door locks, center screen issues, etc. The only difference is you can't see all the cluster warning lights. And it still won't start.

 

would love to hear how it goes. I haven't gotten any codes other than the U0167. When that code happens, it won't start. I tried the mileage reset and that didn't impact the vehicle while the car was running.

 

Finally got to get back at it. battery has been sitting on a bench after fully charging, based on my meter it's 12.57 after sitting for about a week. I decided to pull the instrument cluster just see how bad it was to get out. it's 4 bolts, took 10 minutes. Honestly surprised it's mostly just clips holding it in. pulled it out, car sat for another day. I went ahead and plugged it back in, battery back in, meter connected so I can watch what's going on when starting and running.
started right up - voltage dropped to about 11.9, and went back up to 14.2
fan was on, then went high for about 10 seconds then slowed right back down, voltage is between 14.18-14.21
let it run for about 10 min, drivers door was open, closed it, suspension fired right up, raised no problem, voltage stayed in the same range
lowered the vehicle to access height, voltage dropped to 13.96-14.1,
let it run for about 20 min with no errors

ok so started back up, voltage was all about the same, battery about 12.48 before starting, dropped to 11.9v on start, idling 13.91v (.91-94) spikes about 14.1 .2 when revved and accessories on
I did set the clock.
started putting back together, and as I'm tightening the IC, TPMS error comes on, I loosened it up, and error was gone and car is still running, I think the voltage dropped into the 13.8 range. I accidentally hit the wipers and the meter was sitting on it.
tighten up the IC and checked codes, have lean bank on right/left, not surprised, it's been sitting and idling, but nothing else. I cleared them and restarted and been good for about 15min.
So looks like the alternator works but limited, sweet spot on charging is 13.91-13.94. Battery is about 12.54 when car is off and starts drops a bit.

I turned it off let it sit for about 2 minutes, battery was reading 12.74, and dropped to about 12.54 over 2 minutes, I started it right back up, let it run for 10min
on start up voltage made a quick drop to 11.96, then right back to 13.96, and fluctuated between 13.94-13.96

alternator is new denso unit, fan stay steady on low, so far no errors. The only difference this time from anytime previous, I haven't set the clock yet, I'm going to try that next, i left it just so I had a counter,

wondering if the IC has all these codes and what not, if it needed to be unplugged to clear anything. I'm not saying it's fixed yet, just doing some driveway testing before I get stuck on the road. last time it only took about 5 minutes while running for the errors to show up. I'm about 40min in.