I'd have your battery rechecked by a different shop, make sure they test with a load and not just surface charge. I have seen a low battery do what you described, I've always thought that attempting to start puts a higher load on the battery and kind of "stimulates" the chemical action enough so that a few minutes later it will have enough to kick the starter. (this may be an old wives tale in my mind, I don't know the scientific principle behind it). Also, in newer systems the starter sometimes won't crank slow like the old ones used to, they either work or not and the work/no work threshold is very distinct.

 

I've have a battery tested with a bad cell before, checking the charge it was full, throw a load on it and it failed.

 

x2 on the test under load. If you want to do this at home, put your volt meter across the battery, with truck running. Should be 13.8 - 14.4 volts, based on output of alternator and load on truck. Just at idle not much load. Turn on head lights, AC, interior fan, wipers, killer 2000 watt radio, etc. Should stay above 13.2 even with all the load.

With truck turned off, battery volts will drop some, perhaps down eventually to 12.6. But with head lights on and no alternator running should still see above 12. Just checked mine and 12.2 with head lights on, not running. With inside blower, high beams, and radio on - 11.8. Cranks right up and goes to 13.6 volts with same load, 13.99 with nothing but engine running.

If you have a dead cell, the internal resistance of the battery increases quite a bit, so output volts will drop like a stone with more amp drain. A starter draws like 300 amps.

LR3s have so much electronics, and some of the modules also report faults if battery is weak. Good battery is hard to beat. Of course, tight clean connections are working in your favor as well.

Testing with a meter without having a load is only half the test.

 

So basically what have you done service wise to this vehicle in the 100,000 plus miles
you've owned it? And what have you done to it since your original post in Jan 2012
besides having someone check your battery. If the battery is the original one.. Replace it.
Without reading the fault codes in all the systems, we can just get the good 'ol diagnostic dart board out.

 

Point taken, and agreed. Very little other than routine maintenance (oil and filter changes, fluids, etc).

I've repeatedly inquired with my dealership about whether I should be performing what seems, to me, to be only somewhat more extensive routine maintenance (battery replacement, replacing spark plugs, replacing wiring, etc ... stuff I know to be "tune up" type maintenance) ... and have repeatedly been told it isn't necessary.

I don't claim to be savvy in this regard, so I follow their guidance. However, it does seem that perhaps it is time to replace the battery .. so I suppose I'll just order a replacement and swap it myself if a test under load doesn't produce the expected results. Perhaps it should be replaced even if it does, given that it is at least 4.5 years old).

 

Replacement battery (MTP-H8) is in and the shop said the alternator tested fine (battery that was replaced was testing just below normal, as well).

So far things seem better, but I have had one HDC fault at startup in about 10-12 test starts since picking up the truck. Now, this is opposed to every single start 100% guaranteed, but still I had hoped for it to be entirely absent.

Other issues such as flicker in the dash lights, intermittent reverse sensor and radio cutouts have not been seen thus far -- but I haven't been in the vehicle enough to be confident they're really gone yet.

Hoping for the best.

 

Fault warnings at start up ie trans, park brake, hdc are typically from low battery voltage at start up.
You took the first step and did the most logical repair. (Replaced your 5 year old battery),
and off to a good start since it seems to have eliminated a few of the issues doing so.
Park distance control. radio cut out, trans shifting ,engine performance, seperate faults.
Best advice I can give you is to have all fault codes read, recorded, and cleared, drive the vehicle until faults reoccur, reread for stored fault codes.
If I was to guess here..

Infotainment cut out, probably a radio head unit or amp

Park distance, look at your bumpers and sensors maybe you damaged one, or maybe the fault is as simple as a bad warning speaker for the front or rear.
Without a scan for faults though there's no particular place to start except damaged sensors.

Trans shifting upshift holding and downshift. Take a look at your front tires. If you have mismatched front tires or if on is worn more than the other (one new, and one 1/2 worn or more) you will have shifting issues. if the front wheel speeds detected by the abs module are more than 1kph different you will have strange trans shifting issues. Check your tires and put 2 tires the same size, brand, and tread wear on the front at the least.

Driving/performance issues after cruising at highway speeds
You will need to have your ECM and TCM software checked and updated as necessary.

Most of this will be dealer only repair (sorry) unless you know someone who has access to diagnostic equipment and calibration files.

Recap:
Read record clear codes (all systems), check ecm/tcm and reflash, check your tire wear, and pdc sensors for damage.

Hope this will help...

 

Okay, so, after a week or so of good behavior, problems are beginning to crop up again.

However, they are nowhere near as consistent as before. Parking sensors and errant warning lights on the dashboard remain a thing of the past. HDC faults still pop up randomly.

Of concern, however, is that the radio cutouts and flicker in the dashboard electronic displays (the LCD screens) are back. This time they are 100% tied to vehicle acceleration. I had seen this in the past, but not consistently. Sometimes it would happen when I accelerated, and sometimes it would happen randomly.

Now, anytime I try to sharply accelerate the truck, the radio cuts out and the backlight in the dashboard LCD flickers.

So, thoughts? Battery was replaced and alternator tested OK under load. Should I assume alternator is bad despite the testing?

Vehicle is still accelerating like it is dragging a piano behind it (drastically better in sport mode, but still doesn't feel right), but I'm almost certain that's due to the transmission programming. Haven't been able to get an appointment at the dealer yet.

Continued thanks for everyone's thoughts and advice.

 

follow the negative cable from battery and be sure it is clean and tight on frame ground

 

This thread is a few months old but I wanted to follow up with the OP. My daughters LR2 has the exact radio problem you describe. Did you track the problem down?