P38 battery discharge

Hi,

I have a '96 P38 DT and have the problem of the battery discharging when the vehicle is standing. Two days is long enough to drain the battery so I have to jump start it. I read a suggestion that replacing the IRF receiver with a newer version may help. Has anyone tried this? Did it help?

Also, when driving the vehicle the lights on the heater control switches begin to flicker - this is a non air con model. This looks like a bad electrical connection to me. Has anyone else seen this? If so, what was the fix?

Thanks in advance,
Mike

how old is the battery? it may be time for a replacement?

any decent car shop will check the battery for you.
(for dead cells etc.)

It will almost definately be the alarm not arming correctly. If it can't arm, it tries again and again. On ours it turned out to be the upper tail gate not closing properly. After 2 batterys, we just clened the losk mec and it was fine, but we found it by chance. I think that test book could tell you if it is arming correctly.

yes the rf (plip) receiver could be the problem the old style ones pick up stray signals causing becm to wake up, landrover issued another superseeded part number for these in january so they must still have ongoing issues, but of cousre you should test the battery 1st

Hi,

Thanks for all the replies. The battery is less than a year old and I have had it tested and told it was fine so I suspect the car isn't going to sleep. Hadn't thought of the alarm not arming - will have to get this checked.

On another line I've just noticed this morning that the (gearbox) oil cooler has sprung a leak. Can anyone tell me how difficult this would be to replace?

Thanks,
Mike

Funnily enough I seem to be suffering from the same problem of the battery drain, so I have a simple question, how do you confirm that the alarm is armed ?
Currently I press the lock button on the key fob the indicators flash twice and the doors lock. Does this mean its armed ?
Apologies for the simple questions, but I've only had the car a few weeks.

To perform a becm sleep test on an LP RR,you need to connect a multimeter on a 10a range - between the battery neg lead and the neg post on the battery.If you are careful you can do this without losing the radio code/window settings etc.
After the interior lights go out,the current drain should drop down to less than 30ma after a few mins - sit and watch it,if the drain suddenly goes back up something is waking the Becm.If it stays at less than 30ma then all is well. If it refuses to sleep or constantly sleeps then reawakens,something is upsetting it.Try parking the car in a field in the middle of nowhere and redo the test.If it will sleep in a field then you have something working around where you park your car that is operating on or around 433mhz that is triggering the rf reciever.If you dont have a handy field,you can try disconnecting the rf reciever inside the rhr window.The new rf reciever - pn YWY500170 seems to sort out the issue,all the cars I have fitted them to I have not heard of since.
If the current drain is always above 30ma it is not always the Becm at fault,I have a 4.0se in at the moment which the cd changer always takes 150ma and the lpg ecu takes 120ma - even with a diesel spec battery it still needs driving every few days to avoid a non start.Once you go beyond wether the Becm is sleeping,it can get a bit tricky diagnosing where the power is going,the correct ETM and lots of time/patience are a must.Hope this helps

the receiver does not cause a constant drain so testing it might not help, the receiver gets stray signals from other frequency users which in turn wakes up the becm then causing the battery to drain , you could park it in one place and it would be fine then park it some where else it would go flat, they only cost about £16 and 5 mins to fit so i would just change it anyway

LR GUY said:

the receiver does not cause a constant drain so testing it might not help, the receiver gets stray signals from other frequency users which in turn wakes up the becm then causing the battery to drain , you could park it in one place and it would be fine then park it some where else it would go flat, they only cost about £16 and 5 mins to fit so i would just change it anyway

Click to expand...

Sorry if I didnt make myself clear,by disconnecting the rf reciever you are removing the possibilty of the Becm being kept constantly awake - not that the reciever is consuming power itself.By the way I would like to know where you get your parts from - YWY500170 is about £120+vat retail,I dont think Border holdings would even give that much discount !

lol i might be wrong about the price ill have to check

arggggghhhhhhh i thought they were quite cheap, £100 + vat at my place of work, cant beleive it,

yes i would go with eightinavee's sugestion by disconecting the receiver then leaving the vehicle to stand and see what happens

i have a some problem. my car is RR P38 4.0 SE From USA. i check the fuse box all is OK. The battery is new but it power down after 12 hours.. I disconected IRF receiver too but not any changes.. Alternator working perfectly! I check the negative connection but it is OK! On the Battery I have a 14.1 Volt but in the Cabin I have a 13.8 Volt Withouth any load. If I Turned On the headlight, Heating and press break it will grow down to 12.8 Volt. when I turn On the Headlight the onboard computer will be Restarting..

What should be the reason?
Our country is not a RangeRover Competent specialist and service dealer..

Anyone have any idea what may be the reason?

Check to see if the key out switch out in the ignition switch is sticking, there is a slider/latch in the ignition switch that slides to the side when inserting and removing the key, if the switch is sticking the becm wont sleep either, dont lube the ignition switch though it needs special lube or it may stick worse...

If you get the message ignition key in when you open the door and the key is out, it may be that flattening your battery...?

If you get the message ignition key in when you open the door and the key is out, it may be that flattening your battery...?[/quote]


I verified it but it OK. I verified too the Power when car is sleep mode and here was All OK.


I do not know more than what should be the reason ..

BCM may be the reason? How do I know whether or not corrupt BCM?

Fusebox in a 3 BCM power lines. When I am involved in headlights, the 2-wire power will be fallen. Brake presses in the cockpit during the voltage collapses to the bottom. Any load voltage collapses only when the cockpit.

is it just me - or did i just see....

"ამ fusebox აქვს 3 BCM დენის ხაზები. როდესაც მე ჩართულია ფარები, 2 მავთულზე ძალა იქნება დაცემული. მუხრუჭის დაჭერის დროს სალონში ძაბვა კიდევ ეცემა დაბლა."

There is so much on a p38 its hard to tell, it could be a relay stuck and not shutting a system down..?

if yours it an automatic there is a red led light by the gear selector, observe this when its dark as it shows if the becm has shut down by going out, you will need to sit in the car with all electrics off for a while...

Has your car got any accessories fitted to it...amp towing relays etc...?

The Mad Hat Man said:

is it just me - or did i just see....

"ამ fusebox აქვს 3 BCM დენის ხაზები. როდესაც მე ჩართულია ფარები, 2 მავთულზე ძალა იქნება დაცემული. მუხრუჭის დაჭერის დროს სალონში ძაბვა კიდევ ეცემა დაბლა."

Click to expand...

It's amazing the things you think you see when old age sets in.

JellySpanners said:

There is so much on a p38 its hard to tell, it could be a relay stuck and not shutting a system down..?

if yours it an automatic there is a red led light by the gear selector, observe this when its dark as it shows if the becm has shut down by going out, you will need to sit in the car with all electrics off for a while...

Has your car got any accessories fitted to it...amp towing relays etc...?

Click to expand...

Car Cassette only changed. But it is not already checked miavs power. I think the alarm is broken. Although not reported any errors but can not think of other reasons .. No defender is not being damaged, Alternator Works perfectly.

All information checked in the rave. Such a problem is not fixed.

nacnobi said:

i have a some problem. my car is RR P38 4.0 SE From USA. i check the fuse box all is OK. The battery is new but it power down after 12 hours.. I disconected IRF receiver too but not any changes.. Alternator working perfectly! I check the negative connection but it is OK! On the Battery I have a 14.1 Volt but in the Cabin I have a 13.8 Volt Withouth any load. If I Turned On the headlight, Heating and press break it will grow down to 12.8 Volt. when I turn On the Headlight the onboard computer will be Restarting..

What should be the reason?
Our country is not a RangeRover Competent specialist and service dealer..

Anyone have any idea what may be the reason?

Click to expand...

It sounds like a earthing or a cable issue.Check all vehicle earthing points are clean and making good contact.Check all power.earth cable connectors,there may be corrosion between the cable and connector.

JohnP38 said:

It sounds like a earthing or a cable issue.Check all vehicle earthing points are clean and making good contact.Check all power.earth cable connectors,there may be corrosion between the cable and connector.

Click to expand...

Has been checked and everything is in order. I also do additional wire but still is not working normally.


I think I will have to trash this car ..