Hi all,

I'm having some problems with a 2006 LR3 with 65K miles on it (just bought for our daughter). Anyway, drove it to Florida from TN right after we got it and made it down with no problem other than we need to do a brake job. On our way back, we stopped to get some gas and it wouldn't turn over. Got it jumped and made it back to Chattanooga. I replaced the battery and it made no differences. At that point, every warning light you could possible imagine started popping up - transmission, limp mode, stability control, on and on.... I put a good charge on the new battery and overnight, all cleared for a short time.

So, took it to Land Rover and they replaced my altenator. That worked for a day or two, but one night as my daughter was driving home, it just died on her. We had it towed to Land Rover and they said the transfer case module was starving the system for voltage. Replaced that module and off we go. Lasted another couple of days and same thing, shut down with a million warning indicators and wouldn't start. They now have it again and say it has another bad altenator and that the PCM is also bad now.

My question - It seems they're just throwing parts at this thing to see what works....am I wrong? Could this be that stinking brake light switch that has caused so much trouble in the past for owners? Any and all advice will be greatly appreciated! Thomas

 

Go to your local parts store, they will usually do a free charging system to, you need between 13.6 and 14.4 volts.

 

Mike,

Land Rover checked the new battery I put in it and it checked out fine. They are saying there is parasitic draw from something that is making the altenator work at it's highest possible out put. I've reead many of the threads on the brake light switch causing all kinds of electrical problems that in turn causes all the faults to pop up, but THIS particular Land Rover dealer will not even consider that that could be the problem. I understand may not be as simple as popping that switch in, but you would think they would try it.

Anyone have any other suggestions? The dealers next step is flying in someone from Land Rover to try to figure it out. Thanks

 

hmmmm.... it must be quite a draw, as switching on things like AC, bright head lights, etc., are all normally handled by the alternator and power distribution system with ease. Since the shop computer has not told them where to look, it may be that they'll need to break out the clamp on DC ammeter and test things.

The LR3 system lets the ECU monitor the battery and adjust the power being sent to it, and even adjust idle speed to favor the battery. Plus there is a load management system that will cut back power to some things if battery is weakening.

Any system that depends on sensors will need connecting cables to be clean, tight, and not have a skinned place in the insulation that lets them ground out to adjacent metal. Ground bonding points for battery and such should be clean and tight, the neagtive cable to the frame connection provides the return path for power and is frequently neglected.

Here is the shop manual short pages on the alternator, way more complicated than it needs to be. When you consider how many millions of vehicles still roam the earth without such an advanced charging system.

As for running at high load, that is no different than driving with AC on, lights on, wipers if raining. If alternators could not run at full power, for extended periods, we'd be connected by a web of jumper cables. My D1 has a 100 amp rated alternator. With everything stock turned on it draws 85 amps. Alternator is happy as long as it has air flow for cooling.

 

The only reason that I could see to replace the PCM for something like this, would be if one of the batteries 'exploded' and got acid all over everything back there (both t-case ECU and PCM are located directly behind the battery.

PCM control alternator output, however electrical load management is controled by the HVAC head. I seriously doubt you need a PCM, very rare failure rate on those. TCCMs fail often due to water/acid ingress, and the wiring at it can easily be damaged as well.

I would take it to another dealership before anything else, I agree, they are throwing parts at it. There is pretty much nothing that can draw down the system to the point where the alternator cannot handle it(at least without making a lot of smoke in the process)

If the alternator has failed again, and was replaced by a LR dealership, any dealership can do a parts warranty on that, but you may get a better diagnosis.

 

To: Chattlr3
Did you ever have success in diagnosing the trouble. My daughter is in similar straights and we certainly don't have the financial resources to go through the dealer's "replace with known good part" diagnosis procedure. I'm hoping that I might find some resolution to my daughter's problem through your experience.

My daughter purchased said vehicle through my brother-in-law, without my consultation. According to said brother-in-law, vehicle was always serviced at the dealer. If true, that dealer should be drummed-out of the service corps. A multitude of minor problems are present, but all should have been short-order fixes for any dealer worth his salt. But germane to my inquiry is the parasitic-loss conundrum, which said brother-in-law apparently forgot to mention.

I have gone as far as to disconnected the battery distribution block from the battery at the positive terminal junction. Thus, only the alternator should still remain in-circuit with the battery and with an amp meter between the negative terminal and the ground cable, I'm still reading a 3+ Amp parasitic draw across the meter.

I saw another post of a similar nature in these forums in which the gentleman's vehicle had a failed rectifier on the alternator with leaking diodes that allowed the alternator's charging cable to go to ground, albeit, with some resistance still remaining in the circuit, lest the beast burn itself to the ground. That's presently my best guess until I can get at the alternator for further testing.

Any response from your experience would be most appreciated

 

After jumping through all the hoops to perform a "proper" parasitic loss test [with the jumper and amp meter in parallel between battery post and terminal, key-on key-off, wait 60 seconds, pull jumper, wait and watch while the "intelligent" systems slowly go to sleep] the final amp reading was .05 amps at rest. I guess that's supposed to be considered within the realm of "normal" for these beasts.

I then drove the vehicle about town with an OTC graphing scanner attached to watch voltage. Depending on accessories on and engine speed, system voltage varied from 13.19V to 14.51. Most vehicles would take that in stride with nary a complaint. But it appears to be unacceptable for the LR3 as it went into battery saving mode.

Battery is new, though a little down on its charge at the moment.

Would a new alternator still be advised?

Again, thanks.

 

Duevalvduc,

As mentioned, the dealership threw parts at it but nothing seemed to help. After the first two parts, I told them I wasn't going to pay for anymore until I drove the car for a few days to see if the part actually fixed the problem.

They never even considered that the problem could be the brake light switch, so I just bought one and replaced it myself. Unfortunatley, this did not fix all my problems but did help clear a couple of the warning lights.

I ended up taking it back to the dealership once again and they started on it again. After many calls from the dealership to Land Rover techs., they decided to go through every ground on the vehicle. I have no idea what or which ground was the culprit (don't think they do either) but the problem went away after that trip to the dealership.

So, was it the brake light switch that actually fixed it and the codes just needed to be cleared at the dealership?? Or, was it truly a bad ground somewhere on the car??? I hope this at least gives you some things to try. If you don't have any luck, post back to this thread and I'll call the dealership and see if they will give me some specifics on which ground might have been the issue. I didn't even ask for specifics when I was there because I figured the car would be back there again.....

 

Wow. Many thanks for the detailed response. Because our LR3 still "runs" [while continuously depleting the battery] and we don't have a spare vehicle for my daughter to use in her daily commute to college, I don't get a crack at it but maybe once a week and whatever I do with it must be reassembled and ready to go by the following school day. We presently require a CA smog certification on the beast for tags which has moved this process into overdrive.

We already did the brake switch too - too many reasons not to. Installed the biggest [single] battery possible. cleaned and reassembled all fuses, fusible links, and relays accessible within the engine compartment. Cleaned and conditioned all the major electrical harness connectors in the engine compartment using CAIG Labs cleaner and the separate contact treatment.

Next on the list -- 1. locate and clean the pertinent ground connections, 2. replace the alternator, 3. follow-back and test the circuit which excites the alternator based on battery voltage and ambient temperature.

Any other vehicles I have laid a wrench to has not presented anywhere near the problems in diagnosis and repair for such electrical issues. But the LR3 seems to be designed too-smartly-by-half. Why computer control of things that could easily be handled in the analog realm? Computer controls governing a charging system, unless it is designed redundantly and with copious self-diagnostic capabilities is a recipe for disaster. Computers and their attendant interfaces cannot be ruggedized adequately in a cost-effective manner such that critical systems should ever be made dependent to them.

 

I know this is an old thread, but having the same issues on a 2006 HSE. Just purchased a month ago, already on second battery. Luckily it was replaced for free, but I'd like to get to bottom of the issue before it eats another one. New alternator is on it already and reads 14.25v. I've got an IID Tool on order as well to shutdown BT and SAT, no need for those. It went from fully charged on a tender to dead in 2 days just sitting in the garage.

Does anyone have a good reference guide to find all the ground points? I've read many, many threads, and I think that seems to be a common theme among the fixes.