2008 LR3 Key FOB issue

[carneyb25]

This is my first time posting here. I have a 2008 LR3 HSE with 64,000mi that I have owned for about a year. I just started having what appears to be an electrical issue with the vehicle. A few weeks ago I started having a problem opening the car with the both key FOBs. They won't work at all for the first unlock almost every day. The security light blinks and the alarm goes off when I manually unlock and open the door. Once I put the key in the ignition the car starts with no issues. Once started the keys work fine until the car has been sitting for about twelve hours and then the keys don't work again. I don't know if these other issues are related but right after I started having this problem one day the GPS and the radio/cd player stopped working during one start. I tried to restart and they still didn't work. I drove for about a half hour and tried the restart again and they worked. On a separate occasion I was able to unlock the door of the car but when I put the key in the ignition I was unable to start the car. I left the car and came back about five minutes later and it started up. Both of these problems have only happened once. A couple things that I noticed but may be irrelevant are that the unlock issue started when the nights started dropping below freezing and I have been noticing a slight burnt smell but I thought it might have been due to turning the heat on in the car. Also, I have been hearing a clicking noise coming from the passenger side of the vehicle that has been pretty regular.

Any help would be appreciated, Thanks

[bbyer]

I am going to think about what you are experiencing as to ideas I might have. In the mean time, do you know how to manually unlock your vehicle?

If not, look in the owners manual under the door lock section. Even if you know how, do go out and practice how to unlock the drivers door manually. Roll down a window however before you start to play around. Sometimes the manual unlock mechanism is frozen from lack of use and now is the time to that find out.

I say this as it appears that the problem is related to the power door locks and not the engine start function, As such, if you can get in, you can still go places. It is probably only a question of time before the power door locks will not function - that may be before you have the unlock problem resolved.

[carneyb25]

Thanks for the response. I have been unlocking the vehicle almost every day in the morning manually and I'm sure my neighbors are getting annoyed with the alarm...lol. I say almost every day because there have been a few mornings that it works fine. I might be crazy but it seems like it's the warmer mornings that I don't have the issue. Another think I think I should add is that when I manually unlock the car and use one key to start the vehicle the other key starts to work also without having to put it in the ignition, which leads me to believe that it's not the key battery. Also, I checked the wires in the passenger sill and no evidence of corrosion. I have read that this has been a big problem. I don't think it's a corrosion issue because the problem is intermittent and all the people posting with corrosion issues the locks stop working altogether.

[bbyer]

Clicking and burning from the passenger side suggests the starter solenoid. I say that as I note that you do not have a starting problem yet, just an entry problem so do not worry about the starter for the time being.

I presume you have access to a voltmeter. I would be looking at the battery voltage right after engine shut down - maybe 12.6 volts DC, and prior to start up in the morning, should be 12.2 VDC or better. If you are seeing 11.9 or less, something is probably draining the battery overnight but not enough to inhibit startup. When the engine is idling and most electrical equipment off, the volt meter should show around 14 volts - maybe 13.7 to 14.2 VDC. Any less, maybe something is wrong with the alternator and the battery / system is not running at full strength. In cooler winter weather, the system may run about 14.2 VDC; in summer hot weather, 13.6 VDC. System voltage is ambient temperature dependent.

Also regardless of the voltage numbers, I would suggest you put some sort of charger on the battery overnight. I use a CTEK US3300 as a maintainer. It has a max amp rating of about 3.3 amps @ 14.4/14.7 volts. In my case, I will routinely use it all night for at least a week every few months just to bring the batteries back. I have two installed. The charging systems on our 3's just will not / cannot fully charge the battery regardless of how long you drive.

The reason I suggest the battery charging is that to find the problem, you first have to eliminate the simple stuff - a low battery is that. You may find with a full charge the door locks work OK, then later in the week, the problem starts again. That is progress - to be able to make the problem go away and then watch it reappear.

The key fob works because the roof mounted transmitter receiver hears your key fob signal and then tells the doors to unlock. A low vehicle battery could mean the receiver is hard of hearing. Since both your key fobs work the same way, I agree that the key fob batteries are probably OK, hence I start looking at the trucks battery system instead.

Also below I have provided the hard reset procedure instructions. I doubt the procedure will do any good but it does no harm. What it will do is erase some of the trouble codes that may be building up; I find it is a sure fix for when my radio starts to not want to make sound - display may show the station is there but no sound comes out - and then at a later restart, all is fine.

Hard Reset Instructions

In brief, to start the hard reset process, open the hood but close all doors and let your 3 go to sleep - no radio display etc and no key in the ignition. This will take a couple of minutes and do not open any doors until the reset is completed. (I find that it is often a good idea to have the drivers door window rolled down and the key in my pocket whenever fooling about the vehicle.) Also when I play with a car battery, I remove any rings I have from my fingers.

Disconnect the ground battery terminal from the main starting battery.
Disconnect the positive battery terminal from the main starting battery.

The reason for this order is if a wrench or loose battery cable ends grounds to the body, no arcing or other bad things happen.

(I assume that you only have one battery in your 3. If not, disconnect the others as well and leave them disconnected until after all is done.)

Connect the negative cable to the positive cable. (NOT the battery.) You will need a short length, (a foot or so), of light gauge, (14 to 18 gauge AWG, insulated stranded copper), wire to span between the battery cable ends as there is not enough slack in the positive and negative battery cables for the ends to touch each other.

Hold all together for about a minute or more, (at least two minutes), as you are discharging memory modules within the engine computer and elsewhere. Then it is suggested you then just let all sit disconnected for say ten minutes, (minimum five minutes), prior to commencing to put the battery cable ends back on the battery posts per the following order.

Reattach positive terminal to the main starting battery positive post.
Reattach negative terminal to the main starting battery negative post.

Start engine and hopefully no or fewer warning lights.
Reset time on the radio - note that the station presets are still there as not everything is erased. Nothing much else needs resetting either.

You can now connect up the other batteries if you have a multiple battery setup.

This is a link to a thread in disco3 re the hard reset procedure.
DISCO3.CO.UK - View topic - Hard Reset

This is a link to a thread on Disco3Club re the hard reset procedure.
Disco3Club The Discovery 3 and 4 Owners Club • View topic - How To, Hard Reset on a D3

[carneyb25]

I put a voltmeter on the LR3 today at work after it was sitting for about 3 hours. The outside temp was about 40. Battery before start was 12.3v after starting it was at 14.5v and with a load about 14.2v. When I shut the car off I checked the battery again and it was 12.3v. I went to auto zone after work and had them check the battery with a computer and it said the battery was good but with 71% charge at 14.4v. The charge seems low especially after driving the car for about a hour today. Before I replace the battery I want to put a voltmeter on it in the morning to see what it reads after 12 hours with temps below freezing. Hopefully the door lock issue is a low voltage issue with the battery and this would be a easy fix. What do you think?

Thanks for the computer reset info. I will do that before I change the battery. What would you recommend for a battery replacement and cranking amps? I think I saw that Land Rover changed their recommended cranking amps for the LR3 from the original batteries installed.

[bbyer]

Your voltage measurements sound good - about what they should be so I think the alternator / charging system is good; also probably your battery is good but if you purchase one, note below.

Re purchase of Interstate vs the alternatives, others will disagree and are certain that there are better price deals out there. My view is that they are correct.

My thinking is that the 3 is so fussy electrically that the fewer variables you have the better. The Land Rover LR3 electrical system is "tuned" to a battery of internal construction similar to the Interstate MTP-H7 or H8 batteries. This is what is called a Ca Ca Wet Flooded Lead Acid Maintenance Free battery. This is NOT what is called Absorbed Glass Mat - you want Flooded which is different.

Additionally, what all this means is that it is NOT maintenance free, has a screw type access hole to each of the six cells for adding distilled water or topping up with battery acid, is of relatively old, (classic), style flat lead plate construction with calcium reinforced grids to make it internally stronger, and is specifically designed for starting a vehicle engine and not for running a fridge or winch.

I say tuned to the LR3 electrical system which is better said as adapts to the quirks of the LR3 Pulse Width Modulated, (PWM), charging system as best any battery can. This does not mean it does it well, just better than the alternatives.

As such, first off re your system, before I purchased anything, I would be charging your current battery up on a plug in type charger. One of the quirks of the LR3 system is that it seems unable to fully charge any battery, even a brand new correct one, once it gets down. The charging system will keep a full battery full, but seems unable to get a poorly charged one back up - it is just the way it is. This means you could drive all day and still your battery would be at 71%.

Yes, I know, this does not make sense but this is true of most of the high end vehicles. Bentley "gives" the owner a free CTEK and instructions to keep the Bentley plugged in if parked for any length of time - and not park it at an airport as for certain the engine will not start in about three to five days.

One of the files in the link below has the Interstate Battery chart with dimensions. You will see that the H7 is about 1.5 inches shorter than the H8 and hence fits the battery space better. This is what your LR dealer would most likely install even though the factory recommended size is the H8.

You will also see a data sheet for Deka batteries made by East Penn Manufacturing of Pennsylvania. Their 694RMF H7 and 649MF H8 are of similar construction to the Interstate MTP and in the Euro size and battery post configuration.

Also the battery you purchase must have a flush manifold vented cover so you can hook the vent hose up. The gases that vent off the battery will eat up the transmission computer if not piped away via the vent and hose. You will see the vent hose in some of my jpg's per the album below as well. You should have same in your 3.

DISCO3.CO.UK Photo Gallery - Traxide Dual Battery install in LHDrive

[AcesLR]

Any thoughts on using a dry cell battery?

[bbyer]

Originally Posted by AcesLR

Any thoughts on using a dry cell battery?

I assume you mean an independent power source for the power door lock key fob radio signal receiver. The receiver converts the signals received from the key fob into digital messages and sends them to the Central Junction Box, (CJB), that is also powered full time. Since the receiver must be powered all the time as it must listen for the key fob signal, this would infer a rechargeable power source.

While a dry cell might work, (well not really), one still has to power the actual door locks - the "motors" as Land Rover calls them that do the actual locking and unlocking. This is in part why a near fully charged starting battery matters.

More importantly, and independent of this discussion, it is why you must be certain that your manual key unlock function works as a dead battery can make getting into your 3 a smashing experience.

[carneyb25]

I left the car unlocked last night and checked the battery first thing this morning. The key FOB did not work and the battery was at 12.2V. I was incorrect in my earlier statement when I said that the second key FOB worked as soon as I put the first key into the ignition. Once I put the first key in and started the car that key worked after I took the key out and tested the key lock/unlock. The second key did not until I put it in the ignition and started the car also. It was just a matter of putting the key in and starting and immediately taking the keys out to get them to work again though. Could it be that the receiver is not converting the signal to the CJB but recognizes the keys once they start the car?

I did the hard reset on the battery and I will check again tomorrow morning to see what happens. I don't have a charger yet but as soon as I get one I will put one on the battery.

I think I tracked down the slight burnt smell in the vehicle. I found a leak under the car that looks like it's coming from the front differential pinion seal. I couldn't see if it was getting on the exhaust at all but there was a bit of oil around the surrounding area.

Thank you for all your help and advice!

[bbyer]

14.2 volts DC is pretty high for a battery unless the engine is running. 12.2 VDC is more usual for a near fully charged battery just sort of sitting there after engine shut down. The number might go as high as 12.6 so 14.2 just seems odd.

There are two almost independent circuits within the key fob. Both circuits use power from the battery within the key fob. The engine start circuits use very little power relative to the unlock circuits.

The start circuit only has to initiate a conversation with the CJB engine start recognition logic. The signal from the key fob only has to jump to a transponder coil receiver within the key cylinder and from there it is hard wired.

The unlock circuits require more power from the key fob battery as the radio signal from the key fob has to be strong enough to get to the receiver. Once there, the receiver will hopefully unlock your 3 and turn off the alarm.

You may have more than one problem I think. This is normal and complicates finding the primary problem. This is true of all troubles with the 3; rarely do you have a luxury of a problem being just a single problem. It seems the 3 has the ability to mask problems and then finally some straw breaks the camels back and you get red lights, nasty messages and a general sense of uneasiness.

Re the perhaps defective key fob, internally there is a coin type battery that is soldered onto the circuit board. If seems more often than not, one of the solder joints is broken or more likely loose and leads to poor charging and intermittent operation. It may be that a joint is such that a bit of power makes it thru to the circuit board or that the circuit board capacitors charge up when in or near the key hole.

Link with some sub links re the battery and how to tear the key fob apart.
An LR3 keyfob question - Land Rover Forums - Land Rover Enthusiast Forum

Link with jpg's as to how to tear the key fob apart
DISCO3.CO.UK - View topic - both key fobs not working - help

Link to Digi-Key for their part number P085-ND or Panasonic VL-2330/HFN lithium coin 3 volt 23 mm diameter coin battery.
VL-2330/HFN Panasonic - BSG | P085-ND | DigiKey

Re the leak and the front differential, see the link below re installing a new breather valve. If you have to redo the seal, the new valve will or should be part of the fix. The original ones tend to not breath and hence the seals blow instead - one of Land Rovers secret recalls - well not a recall - just a service advisory.

DISCO3.CO.UK Photo Gallery - Breather Cap Front Differential installation

[carneyb25]

sorry...I meant 12.2V

[bbyer]

Originally Posted by carneyb25

Also, I checked the wires in the passenger sill and no evidence of corrosion. I have read that this has been a big problem. I don't think it's a corrosion issue because the problem is intermittent and all the people posting with corrosion issues the locks stop working altogether.

I put the link in below that you may have already seen as I note that you went on the voyage of discovery and found the evil wires and that they appeared OK.

I thought I would mention them again for the following reasons. The splice could look good but be intermittent. If all else fails, I would again dig into the loom and cut off the telephone spice thing and either install a new one or use my favourite, a small marrette as I can at least see how a marrette works.

There have been reports of the telephone splice things appearing OK but not. Also there are both little red wires and a combo of white and green/white wires down within the loom. The little red coloured conductors provide power to the lights on the power window switches so you might see if the power window switches light up. The wires you are concerned about are the green collection. While I do not know for certain, I believe that there is are similar splices on both sides as it seems some find the splice on the left side and others on the right side. It may be steering wheel location related but I think not.

DISCO3.CO.UK - View topic - Remote Locking from KeyFob not working (Again)

But get the starting battery charged up first - a fully charged starting battery solves alot of problems.

[carneyb25]

Well, I've been charging the battery the last couple days and I haven't had any problems with the key FOBs yet. I don't know if it's related to the hard reset or the voltage of the battery. I think I give it a few more days before I call it a good fix.

I changed the pinion seal today. The vent tube was definitely blocked. I picked up the new style breather at the dealer and replaced it when I changed the seal. When I opened the filler plug there was a lot of pressure. I cut the old breather out and it was blocked. When I took the hub out the retainer on the nut was gone and I think that that the dealer had probably replaced the seal before under warranty. I can't believe they didn't replace the breather at the same time. Anyway, thank you for the info on the replacement.

[bbyer]

My bet is the starting battery state of charge, as it is called, or more correctly the low state of charge will most likely prove to be the the key fob problem. Just keep putting the mains battery charger on the starting battery every night for at least a week.

After you think the battery state of charge is about as high as it can be, you might want to determine what the parasitic draw is. This is the amp draw that the 3 uses when all is supposed to be shut down and the vehicle at sleep. The number should be about 0.5 amps, (a half amp).

If much higher than that, start pulling fuses to determine where the power is going. This is a lot harder than one would think as the hood has to be open to get at the battery fuse box and also to watch the amp meter. You have to bypass the hood ajar sensor, (unplug and jump the two pins or manually close the passenger side hood latch; that is what I did.) If not, you cannot get the 3 to go to sleep with the hood open. Also you cannot open doors as that sets the interior lights on so you tend to have to work thru the rolled down windows re the glove box fuse panel. I dare you to find the door switches that operate the interior lights - you will discover the 3 is no Chev. I eventually pulled the fuse that operates the interior lights if I recall correctly.

Re measuring the amps, I inserted my amp meter alligator clips between the ground cable clamp and the ground post rather than disconnecting the hot side. You get fewer sparks when you fumble the wires etc and you get the same numbers, hopefully near a half amp.

I eventually discovered that the display on the LR overhead entertainment centre would not turn off even when the display door was closed. This was dragging my battery down even though I think the system did eventually shut down after an hour or so on its own. You might find something similar. There are reports of the rear upper hatch switch dragging the battery down as well. The switch still opens the rear hatch as it should but sucks power somehow, which it should not. I have an album in my gallery on replacing the rear hatch switch with the newer RRSport improved switch. In my case, the switch just corroded to death and did not cause any battery problems - just getting into the rear problems.

I guess what I am saying is that as is typical of Land Rover, the problem you think you have is often the result of a problem you do not know you have. It is kind of like you start a thread on a key fob fuss and end up discovering a differential breather problem. You might want to start a separate thread re the breather and front differential seal going - that is part numbers and what you replaced and how much "fun" it was. The flock would like to hear I am certain; also there can be some benefits in sharing the suffering.

If you want to charge up both key fob internal battery's, you can charge them both at the same time by taping, (elastic band), the two key fobs together. As such, when one is inserted in the ignition, the second fob will also soak up a charge as it is appropriately close to the key cylinder. The charge current flows into the battery via some field effect rather than by metal to metal contact. The charging is similar to those electric tooth brush chargers.

[carneyb25]

Hey BBYER,

I thought I would give you an update on this issue. After replacing the battery, checking for an amp draw and leaving the vehicle on a charger overnight I was still not able to resolve the problem. I finally broke down and took it to the dealership and I don't feel so bad now because it has left them scratching their heads. The good thing is that that didn't charge me for anything because they couldn't figure out the problem. They eliminated the key fobs being the issue and they wanted me to change the CJB but they couldn't guarantee it would fix the problem. I told them I didn't want to just throw parts at it and hope that it would fix it. They are going to send a memo to an engineer at LR and see if they can come up with anything. I let you know what if they come up with a good fix.

Thanks for your help, Brian