Transmission fault/HDC fault

The Interstate MTP-H8 series starting battery that I have in my 3 is rated by Interstate at 720 CCA and/or 900 CA. The reserve capacity is 176.

Below is my understanding of CCA and CA as well as RC.

The definition of the Cold-Cranking Amperage (CCA) of an automotive battery is the amount of current a given battery can deliver for 30 seconds at zero (0) degrees F, (-17.8C), without dropping below a specified cutoff voltage (manufacturer-specific, but usually 10.5 volts).

Marine Cranking Amps or Cranking Amps is a rating used to describe the discharge load in amperes which a new, fully charged battery at thirty two (32) degrees F, (0C), can continuously deliver for 30 seconds and maintain a terminal voltage equal or greater than 1.2 volts per cell.

Reserve Capacity, (RC) is a battery industry rating, defining a battery's ability to power a vehicle with no supplemental power. The rating is the number of minutes a battery at eighty (80) degrees F, (26.7C), can be discharged at 25 amps and maintain a voltage of 10.5 volts for a 12 volt battery. The higher the reserve rating, the longer your vehicle can operate should your alternator fail.

In summary my Interstate H8 sized battery is the LR spec battery. The RC of 176 suggests it is what would be regarded as a big battery for a car.

Looks like the hdc faults etc. for me were symptoms of a problem about to occur. They were definately increasing before I got to the point where I was unable to start the car.
Measured the voltage on the batteries when the car was asleep and found the cranking battery at 12.1v and my 2nd battery at 12.3v. I also have a traxide SC40 that was flashing green. I would have thought 12.1v is enough to start the car though. It just gives that pathetic unable to turn the starter motor over sound.
Tried jumping it from the 2nd battery and got the same result. Have put it on the charger for a few hours and have 12.8v but wont start. Will leave it on overnight to give it a full charge but not hopeful. Starting to think it is a solenoid or starter motor problem now. Not sure how to tackle that.

I'll be interested to see if sorting out this starting/battery problem also fixes the faults (will get it looked at properly on Saturday if I can get the car started).

While I did not get all the error messages, and never did I have to walk, first start in the morning was always a question mark. I would often get the growl and weak partial engine turnover and then silence on first try. Subsequently I would get a fairly loud click with each key rotation. After maybe ten attempts and clicks, the starter would grab and the engine start.

I eventually decided the click noise was the starter solenoid. I also think the problem which was resolved by replacing the starter motor complete was probably a defective starter solenoid rather than the actual motor.

To further complement the problem, each night I started putting the starter battery on my CTEK charger. Usually in the morning the prestart battery voltage would be 12.4 VDC and engine start on first attempt was almost a sure thing.

If I did not put the CTEK on, the battery voltage was closer to 12.1 VDC and I would often get the clicking. For the most part of the day, subsequent engine starts were routine. That is why I tended to discount the starter as being the problem but assumed it was some wiring or ignition key problem.

I also have the Traxide Dual setup but my green light was always solid green, not flashing, and that was with no external battery charge.

The bottom line was my alternator was OK, both batteries were OK; much to my surprise, the problem was resolved by installing a new starter motor. I say surprise as the problem seemed to be everything but the starter motor. I think that is because with the 3, there are so many systems that can be wrong, the simple fix, is the last considered.

My independent was able to replace the starter motor by removing a small heat shield accessible sort of at the rear of the right front wheel well, and without removing the wheel well plastic liner, (removed tyre/wheel of course). He also worked from underneath, a combination of the two access points.

It's never as obvious as it might seem....
Got RACV out this morning to diagnose the fault as best they could and see if they could get the car started. They got the car going by cycling the locks a few times..imobiliser related problem. Battery, alternator and starter motor seemed fine.
This might be another clue for these HDC fault problems.

Got the car into LR after it was started as there was no guarantee I'd be able to start it again. Once there the car started ok but came up with the faults 3 out of the 4 times I restarted it. So definately something increasing.
LR found a few random fault codes including crank angle sensor which they know isn't the reason. They are looking to replace a ground cable with a new version as feedback/interference in the ground cable has been the cause of a number of these faults in other vehicles. Hopefully this is the fix for at least my car, possibly others with these random faults. Will let you know when I get it back.

My petrol 4.4L V8 LR3 has two ground cables, the short one you see from the battery negative post to the bolt on the fender right near the battery and a second longer ground cable somewhere under the engine between the frame and going to the starter motor.

I did replace the short one between the battery and the fender, but to no avail as the problem was the starter. I just wondered which ground cable the dealer was referring to assuming the diesel units also have more than one ground cable.

Based on the cost it sounds like the longer one.

I do not know if one can compare prices across the oceans, and LH vs RH drive but the short one between the negative battery post and the fender was about sixty dollars plus tax from my LR dealer.

The part number was YTB500300 but that is for a left hand drive vehicle where the starting battery is located on the right side of the vehicle.

The cable part number that I had replaced was LR026050 (EARTH LEAD 4.0 V6). Picked the car up today and have started it around 10 times with no faults being reported. So looks like this fixed the immediate problem. Time will tell if this fixes the random faults for good.

Replacing that under the engine ground cable may be the solution - it is obscure enough so it sounds about right. Maybe it is common with all these new vehicles, but why a fix for some of these problems has to be so indirect, it really is a concern.

This is why with my starting problem, everything but the starter was looked at and the starter motor, while not forgotten, was last on the list of possible problem areas.

Hopefully in a few weeks you will beable to say that it looks like replacing the longer hidden under the engine ground cable that no one knows even exists was the fix for a starting problem.

Well done and good luck.

Thought I'd report back 3 weeks after replacing the ground cable.

Faults completely dissapeared for a couple of weeks I thought..SWMBO forgot to tell me that they were still occurring. Happened again within a week of installing the cable, probably 3 or so time last week and today, occurred on 3 separate occassions. I think there is also a EPB fault as SWMBO reports there was screeching noise when shutting the car off today several times but can't quite describe it (EPB would be applied about the same time)
I've reported EPB concerns the last couple of visits but LR recon it checks out OK. I suspect this is part of the fault.