Range Rovers Forum banner

1 - 20 of 41 Posts

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #1 ·
I acquired a 2001 P38, about six weeks ago, and I am still trying to iron out its faults.
I have cured a false Headlamp failure, unlocked an EAS fault, and repressurised the system, but still experience a totally flat battery, in a few days, of not being driven.
Today, I disconnected the rf aerial, for the central locking (a known BeCM wake-up cause, I believe), but the fob still works.
Whilst in the rear luggage space, I noticed the Satnav CD player was 'live', and periodically attempted to access the disc (removed). Is this normal, in an unlocked car?
Some time after locking the car, I noticed that this CD drive was still 'active', and presumably runs all night - in a locked car !!
How can I switch this off, but have it ready for use, when I switch on, on the dashboard?
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,225 Posts
Yes, the RF is responsible for a lot of BECM waking up issues and draining the battery, but there are also a lot of other 'activation' inputs to the BECM that will keep it awake too.

The navigation unit might be your cause. It should stay on after the vehicle is shut off as it finishes writing data to it's memory (like last GPS position and things like that I think), but it should go to sleep itself after a couple of minutes.

If the Nav unit isn't going to sleep, then it could be the cause of your drain. It won't keep the BECM awake, but it will still draw power.

If you sit in the vehicle in the dark, you should be able to see the red light by the 'P' on the gearshift (when in Park obviously) very dimly lit when the BECM is awake. If you sit in the vehicle then after a couple of minutes then you should see it go out. The vehicle doesn't need to be locked - the BECM will still go to sleep even if there are doors open - it just times out after a couple of minutes of inactivity and then will sleep.

If the red light doesn't go out, then either the RF recevier is still keeping it awake, or one of the other inputs is stopping it from sleeping.

Hope this helps.

Marty
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #3 ·
Thank you, Marty,
I have tried sitting in the car, in the evening, and watching the led next to 'park'.
It appeared to go out, after a couple of minutes, but I did not sit there, for too long, to see if it woke up, again.
At that point, I was unaware of the Navigation disk player, appearing to be constantly powered up, evn when the vehicle was locked.
I think, like you, that this may be the cause.
I just need a fix for this drain, and I shall be able to use my beautiful car.
Thank you for your advice, Chris
 
G

·
simply pull the connector of the satnav for a few days and see if this cures your battery drain problem.... then you know if the datnav is the cause..... after that you can start looking to fix it...

you say it is looking for a disc but there is no disc in.....what if there is a (good and working) disk in the player?
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #5 ·
Thank you, RogerB,
This will be my first step, when I can find where to disconnect it.
My understanding was that the CD was only accessed, when uploading new data into the Nav computer's memory, and so I removed it, in an attempt to inhibit this constant attempt to read it
Further, in all local journeys, I 'switch off' the Sat Nav, but presumably this just shuts off the dashboard display?
The bloke who sold me the car, assured me that an 'expert' had checked out the electrical system, and found no faults, but he kept the car in his garage, on constant trickle charge, which is just not convenient to me, and should not be necessary !!
The real problem, I think, is that the Nav system is not shut down, when the ignition key is turned off, and removed.
I am gradually working through all the problems that I inherited, but driving it a short distance, this morning, was pure joy.
Best wishes,
Chris M
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,225 Posts
Try it with the nav disc in it still. In theory, it should still shut down after a couple of minutes anyway.

The disc is used all the time by the system when it's running, as the disc holds the maps, and is read whenever you look for something, or when it tries to plan a route.

There is another disc which has the firmware upgrades on it (not actually available to the public) but this is the disc that the unit's software is on, which is read and then programmed to the memory of the nav computer.

Under normal use the mapping disc should stay in the drive.

If it won't turn off with it in the drive either, then the connectors to the nav computer are in the back of it. They are accessible 2 ways - by getting some small screwdrivers (or the proper removal tool - or maybe a bent piece of coat hanger even) to go into the holes on either side of the unit. pressing in there will release the clips for the unit and allow it to be pulled forwards to then access the cables at the back.

The other method is to remove the piece of trim which sits on the right of the loadspace - which has 3 trim fasteners and a single screw (accessible when you fold the seat down. There are some slips along the window line aswell which, once released allow you to get at the back of the nav computer (from memory before I pulled my one out) to disconnect it.

Just remember if you remove the trim to poke the seat release button back up through the hole in the trim as it can flop over and get stuck under the trim - which can be a pain to then release the seat again after you've raised it and THEN realised the button is under the trim!

Hope this helps,
Marty
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
474 Posts
I believe you should get a new battery, the drain you are talking about will not weaken it at all.
 
G

·
4 long nails that just fit in the holes of the front of the satnav will unlock the unit to be pulled out as well (or blaupunkt/philips/VDO radio keys)
 

·
Banned
1995-2002 Range Rover P38A
Joined
·
3,952 Posts
1+ on replacing the battery. Unless it's less than 2 years old and hasn't been left in a discharged state, it will be beyond it's sell by date anyway.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #10 ·
Dear marty_nz,

Thank you once again, for your very helpful reply. There is certainly an impressive brotherhood of P38 owners, and I am very thankful.

I was not aware that mapping data was drawn from the CD, and assumed that it was all loaded into memory. I see now that this just relates to the software.

Thank you for your clear explanation of how to access the connections. I discovered the method, and seat release pitfall, when I removed the opposite trim, to access the rf aerial connection.

I will replace the disc, and see whether that cures things.

Again, many thanks for your continuing interest.

Chris M
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #11 ·
Dear xrav22,

The chap who sold me the car, said that he had fitted a new battery, and it appears to be so. Mind you , he also said that a R/R expert had checked the wiring, and found no fault. We shall see !

Thank you, Chris M
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #12 ·
Dear rogerB,

I am familiar with these 'radio removal' pins, from aircraft radios - but thank you, Chris M
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #13 ·
Dear gilbertd,

I think the battery is quite capable, but it cannot sustain several days of constant - day and night - discharge. When I find the cause, I'm sure all will be resolved. Thank you, Chris M
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
474 Posts
I would at least bring it to be tested, because if it was new and he left the lights on 1 time and drained it all the way it will never be the same. Just saying I don't think he would mention that selling point
Good luck
 

·
Banned
1995-2002 Range Rover P38A
Joined
·
3,952 Posts
I think the battery is quite capable, but it cannot sustain several days of constant - day and night - discharge.
Have you actually connected an ammeter and measured how much current drain there is? For a couple of minutes after switching everything off and locking it, there will be a couple of Amps being drawn, after that it should drop to a few milliamps. As said, even with a new battery, one deep discharge will damage it so it will go flat quicker.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #16 ·
Thank you - I am aware of this test, and since the radio code has been lost already ( but I have a note of it), it could do no harm.
The Nav system appears to have survived several total discharges, without ill effect. Maybe the 'power on' LED in the rear compartment does not signify too much current draw?
Looking at the wiring diagrams, there are several connections between the Nav computer, and the BeCM, so maybe they are keeping each other awake !?
I may not get a chance to try the current flow test tomorrow, but I thank you, again, for your helpful suggestions.
We will get there, in the end !
Chris M
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #17 ·
I thought I had replied to this latest post, but it seems not to have appeared.
I am familiar with this parasitic drain test, and will give it a try, when I get a minute.
Researching, in another place, to discover something about the Nav power LED being 'on' all night, I came across this.

Originally Posted by rrtoadhall
How long are you waiting for the LED to go out? There have been reports of 7 and 8 minutes for the unit to go to sleep. Unless your battery is going dead overnight I wouldn;t mess with it.



I have waited for hours, even over night. The battery was going flat within two days. I have a new battery in it now. I have read the RAVE and it clear states:

"The navigation computer uses non-volatile memory to store settings and configuration information when it is powered
down. This process takes place just before the computer turns off and occurs approximately one minute after all K-Bus
activity has ceased. Once the power down sequence has been completed, the red LED on the front of the unit is
extinguished."

The question remains, is it a BeCM fault which is keeping it awake?
I am reluctant just to disconnect it, since this was part of the spec. for the 'new' car, to replace my '89 Classic.
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,225 Posts
The connections from the BECM to the Nav system are as follows:
C1349 (Nav Computer), Pin 1 - Purple Wire - 12V constant feed
C1350 (Nav Computer), Pin 3 - White/Pink Wire - 12v switched feed
C1350 (Nav Computer), Pin 10 - Yellow Wire - Vehicle Road Speed
C1350 (Nav Computer), Pin 1 - Green/Brown Wire - +12V when reverse selected
C0820 (Nav Screen), Pin 1 - Red/White Wire - Illumination feed (when sidelights are turned on)
C0820 (Nav Screen), Pin 4 - Purple Wire - 12V Constant feed
C0820 (Nav Screen), Pin 5 - White/Pink Wire - 12v Switched feed

None of these should be keeping the Nav system awake though. The only thing that could do it without affecting the BECM is the switched feed - but that relay also powers switched power to the radio and HEVAC, so if there was an issue with that, then I would have thought that there would be other issues aswell that you would have seen by now.

I agree the best thing to do would be to physically disconnect the nav unit (both connectors) and see if that makes a difference.

If you do the ammeter test as Gilbertd mentions, then you can measure the current draw both with and without the nav unit plugged in.

To be fair, I didn't think that the factory nav system wasn't that great (had it on my 2001 before I pulled it out and replaced it) - even with up to date maps, you still couldn't postcode search and it was pretty slow at times!

I'd just disconnect it for a while and see what the difference (if any) it makes - it will at least hopefully narrow down your issues.

Marty
 

·
Registered
Joined
·
253 Posts
Word of warning. The memory to the sat nav *IS* volatile. If you disconnect power to the sat nav unit, either by pulling the plugs or disconnecting the battery before it has gone through its power down sequence it can and often does wipe the flash memory. There is no one in the UK anymore, i know of, that can reflash the memory, so it's a new nav computer.

If the battery is recent, have you checked the alternator output, anything high or low will toast the battery. one of ours had a high alternator output (15.?v) due to a faulty regulator and toasted a new battery. alternator should be from 14.2-14.8 (if i recall correctly) anything outside of that will damage the battery.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
29 Posts
Discussion Starter · #20 ·
Marty,
Thank you for your very comprehensive analysis, of the BeCM connections, and of the consequence of just pulling the appropriate relay.
I agree that the ammeter test is the only definitive method, of tracing the constant 'switched off' battery consumption.
I could just disable the Nav system, of course, but this was part of my 'must have' spec, when I chose this vehicle. I am reluctant, just to abandon it, but it does seem to be the source of the trouble.
I agree that it is a bit 'steam age', and far inferior to my little PDA, where all the mapping data, and incidentally, a 'half mill' aviation chart, is held on a micro SD card. However, it is preferable to sticking this on the windscreen with a sucker, especially since the heated screen filaments, interfere with the satellite transmissions!
I peered through the back window, several times, during the night, and found the Nav unit powered up, and occasionally accessing the disc, it seemed, and it has been doing it, all day, up to now!
There is no doubt in my mind, now, that this is the cause, but I am a bit reluctant just to disconnect it, in the light of the susbequent post, which warns against powering down, whilst the device is writing to its memory.
Having said that, it has survived several almost complete battery depletions, but not a total disconnection. I am afraid to disconnect it, now !!
Thanks again, Chris
 
1 - 20 of 41 Posts
Top