Hi guys yet another issue to solve !
Over the last 4 weeks I have suffered battery drain, last charged in between christmas and new yer and this morning completely flat ! I mean flat flat.
Battery less than 7 months old 13 volts idle car charging at 14.38
No lights left on inside the car at all
No extra consumer units on, sat nav main power disconected and when I bought it RF receiver was disconected as well which I re connected and had no issues with it even leaving the car for 2 weeks and still loads of power
battery is a yussa 5000 and in good health
seems the previous owner had the same issue and had not found the cause............I dont know where to start ? still have to do gearbox and thought while I am "off road" I will try and fix this as well.
Last time went flat in 4 days ! seems a strong drain even for a p38 !
Are there any other, seemingly unconnected, faults that might cause the BeCM to stay awake? Assuming the gearbox is still in there you can check that the BeCM sleeps by sitting in the car in the dark. With everything switched off, the gear position LED will be glowing dimly next to whatever gear it thinks it is in. After 2 minutes of sitting very still with everything switched off, it should go out. That tells you the BeCM has gone to sleep. If it doesn't, something is keeping it active. Do you have a meter so you can check the actual battery drain?
Otherwise, unplug the timer relay ( under passenger seat) to check it's not the eas levelling that's causing your drain, will also give you a good idea how the air system is,,
But that will only kick in every 4 hours or so and if the car is parked on the flat it'll turn off almost immediately. If it's on lumpy ground so it has to try to level (or there's a leak) it'll kill a poorly battery fairly quickly but a decent one won't go flat that quickly.
I've heard that parking near certain types of transmission towers can lead to battery drain on P38s and on other vehicles...?
Hi, thanks for all the replies they are all greatly appriciated.
She has 4 new bags on her no leaks and only does the normal god I need to be level range rover thing.
Yes I have a meter that I can try..not 100% sure on the way to go ?
I have thought of disconcerting the RF again and see if that makes much difference just seems heavy for an RF drain ?
I am also posting as to try and help others in the future so thanks in advance again all comments more than welcome.
Gilbertd wrote:
Are there any other, seemingly unconnected, faults that might cause the BeCM to stay awake? Assuming the gearbox is still in there you can check that the BeCM sleeps by sitting in the car in the dark. With everything switched off, the gear position LED will be glowing dimly next to whatever gear it thinks it is in. After 2 minutes of sitting very still with everything switched off, it should go out. That tells you the BeCM has gone to sleep. If it doesn't, something is keeping it active. Do you have a meter so you can check the actual battery drain?
Good idea I did'nt know about the led will try that this evening and post my findings thank you.
dazer2000 wrote:
Gilbertd wrote:
Are there any other, seemingly unconnected, faults that might cause the BeCM to stay awake? Assuming the gearbox is still in there you can check that the BeCM sleeps by sitting in the car in the dark. With everything switched off, the gear position LED will be glowing dimly next to whatever gear it thinks it is in. After 2 minutes of sitting very still with everything switched off, it should go out. That tells you the BeCM has gone to sleep. If it doesn't, something is keeping it active. Do you have a meter so you can check the actual battery drain?
Good idea I did'nt know about the led will try that this evening and post my findings thank you.
Just checked, LED beside the gear selector but go's out as soon as I switch car off ??? any good ???
When you switch the car off it goes out but not completely, it will still be glowing very dimly. It does need to be dark and you may need to let your eyes acclimatise before you can see it. If the BeCM is still awake, it'll be drawing about 3A, once it is sleeping, it should be down to about 20mA (0.02A). The reason why a source of RF will cause the battery to go flat is because the receiver is seeing a signal so keeps the BeCM awake waiting for the correct code (which it never gets) so you've got the 3A drain there all the time.
With everything switched off and the doors all closed (but bonnet open), set your meter on the 10A scale (usually means using different sockets on most cheaper meters). Connect one lead to the battery negative terminal and the other to the battery negative post. Then carefully lift the negative terminal off the post so the connection to the battery is still there but via the meter. The reading you get on the meter will be how much current is being drawn. If around 3A, it should drop as soon as the BeCM goes to sleep, if around 20mA, it already has. If anywhere between these two, something is drawing current.
Gilbertd wrote:
When you switch the car off it goes out but not completely, it will still be glowing very dimly. It does need to be dark and you may need to let your eyes acclimatise before you can see it. If the BeCM is still awake, it'll be drawing about 3A, once it is sleeping, it should be down to about 20mA (0.02A). The reason why a source of RF will cause the battery to go flat is because the receiver is seeing a signal so keeps the BeCM awake waiting for the correct code (which it never gets) so you've got the 3A drain there all the time.
With everything switched off and the doors all closed (but bonnet open), set your meter on the 10A scale (usually means using different sockets on most cheaper meters). Connect one lead to the battery negative terminal and the other to the battery negative post. Then carefully lift the negative terminal off the post so the connection to the battery is still there but via the meter. The reading you get on the meter will be how much current is being drawn. If around 3A, it should drop as soon as the BeCM goes to sleep, if around 20mA, it already has. If anywhere between these two, something is drawing current.
Cheers mate I am going for a look now
dazer2000 wrote:
Gilbertd wrote:
When you switch the car off it goes out but not completely, it will still be glowing very dimly. It does need to be dark and you may need to let your eyes acclimatise before you can see it. If the BeCM is still awake, it'll be drawing about 3A, once it is sleeping, it should be down to about 20mA (0.02A). The reason why a source of RF will cause the battery to go flat is because the receiver is seeing a signal so keeps the BeCM awake waiting for the correct code (which it never gets) so you've got the 3A drain there all the time.
With everything switched off and the doors all closed (but bonnet open), set your meter on the 10A scale (usually means using different sockets on most cheaper meters). Connect one lead to the battery negative terminal and the other to the battery negative post. Then carefully lift the negative terminal off the post so the connection to the battery is still there but via the meter. The reading you get on the meter will be how much current is being drawn. If around 3A, it should drop as soon as the BeCM goes to sleep, if around 20mA, it already has. If anywhere between these two, something is drawing current.
Cheers mate I am going for a look now
OK just done the sit in test as suggested and your spot on....thank you, I sat inside her ignition on then off and led glowed bright until i turned off the a low dim glow, I locked the doors and sat there for a couple of minutes and yes the dull glow went out so at least I know the BCEM is going to sleep...............yes ?..................
So if that ok ( and hope it is for all the right reasons ) where next ?
With the vehicle asleep, start sticking your ammeter across the fuse sockets (not the Maxis) and see which ones are drawing current and how much. There's also the possibility that a neighbour got a new toy (weather station, wireless smoke alarms etc) for Christmas and that's waking your rf receiver so unplugging that might make a difference
Over on the other site they'll blame just about every type of radio transmitter known to man to cause the receiver to wake up but they use a different frequency to us civilised people in Europe. The fob operates on 433.9MHz but so do numerous other 'momentarily operated short range devices' to give them their correct title. That means wireless doorbells, weather station transmitters, wireless burglar alarms, oil tank level senders, video senders (the return for the remote),etc. All of these should only wake up when needed but unlike most things that stop working when they go faulty, most seem to go on permanent transmit when they go faulty. In saying that, if there is something that transmits every 10 minutes (like a very keen weather station transmitter), every time it transmits the alarm receiver wakes the BeCM up so it sits there drawing 3A for 2 minutes until it goes back to sleep.
Orangebean wrote:
With the vehicle asleep, start sticking your ammeter across the fuse sockets (not the Maxis) and see which ones are drawing current and how much. There's also the possibility that a neighbour got a new toy (weather station, wireless smoke alarms etc) for Christmas and that's waking your rf receiver so unplugging that might make a difference
Do you mean the box under bonnet on right hand side and the ones on the BCEM ? and what is MAXIS ?
Gilbertd wrote:
Over on the other site they'll blame just about every type of radio transmitter known to man to cause the receiver to wake up but they use a different frequency to us civilised people in Europe. The fob operates on 433.9MHz but so do numerous other 'momentarily operated short range devices' to give them their correct title. That means wireless doorbells, weather station transmitters, wireless burglar alarms, oil tank level senders, video senders (the return for the remote),etc. All of these should only wake up when needed but unlike most things that stop working when they go faulty, most seem to go on permanent transmit when they go faulty. In saying that, if there is something that transmits every 10 minutes (like a very keen weather station transmitter), every time it transmits the alarm receiver wakes the BeCM up so it sits there drawing 3A for 2 minutes until it goes back to sleep.
Yes I have heard of this, I have thought of trying this as so to eliminate it, I will try this tommorow, I did this on my last P38 and did not stop her draining and then all of a sudden it stopped !
There are a few things which can wake up the BECM but it is ~95% an external RF source as already indicated dazer2000...
A useful (GEMS/1998) document can be found on http://rave.stringsandints.com/ In the list see item 'BECM SID CONSOL' (from page 10 or so)
I really like how Land Rover state within that 'if the LED stays on you should replace the BECM'
obviously they really meant 'you should make an appointment with your Bank Manager'....
or nowadays preferably just talk with one of the BECM experts on this site !!
That is sounding even better..........95% RF
Can the BCEM be repaired if it does go faulty ?
Yes- the under bonnet fuses to start with and initially avoid the Maxi Fuses
dazer2000 wrote:
Do you mean the box under bonnet on right hand side and the ones on the BCEM ? and what is MAXIS ?
Orangebean wrote:
Yes- the under bonnet fuses to start with and initially avoid the Maxi Fuses
dazer2000 wrote:
Do you mean the box under bonnet on right hand side and the ones on the BCEM ? and what is MAXIS ?
Great I will give them a go with the meter, might do it in my mates workshop
Maxis are the half dozen really big fuses.