BECM not going to sleep ( it's not the r/f receiver )

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carnutter5

carnutter5

New Member
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22
Location
Chepstow
Hi all, I have a 97 4.6 P38. I have had the car a few weeks and knew it had a few gremlins. The first thing I did was check to see if the blue r/f receiver aerial wire was disconnected - it was and the remote locking still works as it should, provided I am close enough of course.
The BECM is not going to sleep though - ( from all I have read, I therefore don't think my drain is coming from the r/f issue ) I have been through a few checks and I can hear a faint electrical hum coming from the BECM when I switch off - I have checked the "key in ignition" message and it stays on ( I think I am right in saying it is supposed to switch off after 2 mins when the BECM goes into sleep mode ? The BECM continues to hum well after the 2 mins.
I have 12.5 volts at the battery when off and 13.85 at the battery when it is running - the battery may need replacing but I can't see why this would affect the BECM. The BECM goes quiet when I pull all three maxi fuses, unsurprisingly.
Any ideas would be greatly appreciated.......
Thanks.
Paul.
 
carnutter5 said:
Hi all, I have a 97 4.6 P38. I have had the car a few weeks and knew it had a few gremlins. The first thing I did was check to see if the blue r/f receiver aerial wire was disconnected - it was and the remote locking still works as it should, provided I am close enough of course.
The BECM is not going to sleep though - ( from all I have read, I therefore don't think my drain is coming from the r/f issue ) I have been through a few checks and I can hear a faint electrical hum coming from the BECM when I switch off - I have checked the "key in ignition" message and it stays on ( I think I am right in saying it is supposed to switch off after 2 mins when the BECM goes into sleep mode ? The BECM continues to hum well after the 2 mins.
I have 12.5 volts at the battery when off and 13.85 at the battery when it is running - the battery may need replacing but I can't see why this would affect the BECM. The BECM goes quiet when I pull all three maxi fuses, unsurprisingly.
Any ideas would be greatly appreciated.......
Thanks.
Paul.
Click to expand...
The key in ignition messge should go when you remove the key from the ignition, the shutter & switch is sticking, get some graphite lock lube and fix that.
Just because the blue wire has been removed from the RF receiver, it does not mean the RF receiver is not the problem, the exact opposite in fact. It demonstrates there is a problem with the RF receiver that the previous owner has tried to overcome by removing the aerial wire. The MK1 & MK2 receivers can still keep the BECM awake even with the aerial disconnected, worse, they can also cause the locks to burn out when they run amok.
 
Ok, thanks for the quick reply - if I disconnect the electrical supply from the r/f receiver so it can't do anything at all, will that help ? I live in the middle of nowhere and rarely bother locking the car anyway. The key in message does indeed go when it is removed, but I read that with the drivers door open and the key in the "0" position, the message should go out after 2 minutes or so, with the key still in ?
Is that not correct then ? How do I find and then presumably isolate the circuit that is causing the BECM to stay awake - is there a way of isolating the alarm system ?
I am waiting for my Nanocom to arrive having ordered it on Wednesday......
Thanks for anything further.
 
carnutter5 said:
Ok, thanks for the quick reply - if I disconnect the electrical supply from the r/f receiver so it can't do anything at all, will that help ? I live in the middle of nowhere and rarely bother locking the car anyway. The key in message does indeed go when it is removed, but I read that with the drivers door open and the key in the "0" position, the message should go out after 2 minutes or so, with the key still in ?
Is that not correct then ? How do I find and then presumably isolate the circuit that is causing the BECM to stay awake - is there a way of isolating the alarm system ?
I am waiting for my Nanocom to arrive having ordered it on Wednesday......
Thanks for anything further.
Click to expand...

I'm not aware that the key in ignition message will go away after 2 minutes. I don't think the BECM will go to sleep with a door open and the key in, may be wrong on that.
If the car is an auto, you can check if the BECM is going to sleep by locking the car and watching the top light on the gear selector which will glow faintly until the BECM goes to sleep. Search for BECM sleep test.
The alarm can be disabled in the BECM with a Faultmate and presumably also with a Nanocom.
The most common cause of the BECM staying awake is the RF receiver, how do you know it's staying awake?
 
Reconnected everything around the r\f and checked for the faint glow from the auto selector area when locked - nothing. Is it an LED ? Where exactly should I be looking ?
btw, the central locking is only locking ALL of the doors some of the time - I suspect this might be part of the problem ? Currently it is unlocked - as it has been since I bought it - would the r\f receiver still be playing up the BECM whilst the car is unlocked and alarm off ?
 
carnutter5 said:
Reconnected everything around the r\f and checked for the faint glow from the auto selector area when locked - nothing. Is it an LED ? Where exactly should I be looking ?
btw, the central locking is only locking ALL of the doors some of the time - I suspect this might be part of the problem ? Currently it is unlocked - as it has been since I bought it - would the r\f receiver still be playing up the BECM whilst the car is unlocked and alarm off ?
Click to expand...

The top light of the gear selector indicators.

Right, a quick search has brought up the following:-


BECM:
To test for sleep mode:

Switch off interior lights (hold central button on light above centre of dash for several seconds)
Open Drivers door window and close door.
Insert Ignition Key and turn to position 2
Turn to off and leave the key in the barrel
Open the drivers door and the key-in message will be displayed on the instrument pack
The interior lights should still be off.....
Wait for 2 minutes (sometimes closer to 2 minutes 30 seconds) for the BeCM to go to sleep
If you can still see the Key-In message then the BeCM is awake.

If the message has gone, and you do something to wake the BeCM (try opening the bonnet), you'll get a bleep from the dash. This indicates that the BeCM has been awakened.

If you do this with an ammeter in series with the battery lead you'll see the current draw around 0.6 to 1A when the BeCM is awake and more like 0.030A when it's asleep.

The RF reciever can cause problems locked or unlocked. Which doors are giving problems?

Is the carpet in the drivers footwell wet by any chance?​
 
Just been reading this whilst sat outside mothercare (wife shoping)
Everythings off keys on dash and the "p" is dimly light and has been for around 10mins
Does it need to be locked or owt?
Dont know if its a fault or not as never had a batter drain with this car! But then I wouldn't cos its got a big arsed tractor battery in
 
Ok, run through the above - definitely no light on the gear selector unless ignition is on - but the key in ignition message goes out, as it should - the mistake I was making was leaving the bonnet open ! I think I will put a new battery in to eliminate that particular aspect of my head scratching. Perhaps the battery is going flat because it is past its sell-by date.

re wet carpet in the footwells - that was the first thing I checked ! Fortunately not, but I have already removed two blend motors as they were knacked. I suppose it might make sense to change those pesky O rings when I fit the new motors. It's never ending, but my eyes were wide open before I took the plunge, again.................
 
Last edited:
carnutter5 said:
Ok, run through the above - definitely no light on the gear selector unless ignition is on - but the key in ignition message goes out, as it should - the mistake I was making was leaving the bonnet open ! I think I will put a new battery in to eliminate that particular aspect of my head scratching. Perhaps the battery is going flat because it is past its sell-by date.

re wet carpet in the footwells - that was the first thing I checked ! Fortunately not, but I have already removed two blend motors as they were knacked. I suppose it might make sense to change those pesky O rings when I fit the new motors. It's never ending, but my eyes were wide open before I took the plunge, again.................
Click to expand...

Battery Megastore on line, Alpha line 1000CCA 135AH, biggest that will fit. No affiliation.
 
carnutter5 said:
Ok, run through the above - definitely no light on the gear selector unless ignition is on - but the key in ignition message goes out, as it should - the mistake I was making was leaving the bonnet open ! I think I will put a new battery in to eliminate that particular aspect of my head scratching. Perhaps the battery is going flat because it is past its sell-by date.

re wet carpet in the footwells - that was the first thing I checked ! Fortunately not, but I have already removed two blend motors as they were knacked. I suppose it might make sense to change those pesky O rings when I fit the new motors. It's never ending, but my eyes were wide open before I took the plunge, again.................
Click to expand...

The light glows very dimly and can only really be seen when it's dark.
Lock the car and look at the gear selector carefully when dark and you should see a dim glow from the selector light. It should go out in 2 to 3 mins.
 
One slight problem, the becm will go to sleep if any of the doors or tailgate/ bonnet is open or closed, locked or unlocked. The key in message is easiest way to see if becm is going to sleep or not, a faint glowing LED on the H gate is to next easiest If you are in P then the P LED will glow dimly. You can also just simply check the current flowing from the battery to see if the becm is asleep (current will drop by ~ 2 amps when becm goes to sleep).Don't forget to switch off the interior lights before doing the 2 min check.
 
Becm humming faintly. I'm familier with that buzzing noise.

There's a good percentage of becm's that we repair come to us with battery drain.
If you pay the postage you're more than welcome to send me your becm & I'll test it for you, that is once you've gone through everything else than be causing the drain.

If you remove the RF receiver completely you won't be able to start your car, unless the Immobiliser has been de-activated, but you can disconnect for testing purposes.
 
Thanks for that - apparently anyone who downloads their app gets a 10% discount and its free delivery on top - just waiting for an email back. Battery I was looking at is 130Ah and 1000cca for £90 delivered including the 10% off.

Reference the battery drain - as the key in ignition message goes off, I think the BECM could be going into sleep mode and my issue is a duff battery. It was totally flat when I bought the car so maybe the cold weather has finally finished it off. I am waiting for my Nanocom to arrive, so I will have a play with that as well.

I might just put an Optimate on the car as I only use it at weekends. I have one on my Merc and it has given me piece of mind for the last two years - always topped up when I want to use it.

One way or the other, I am going to get there - I bought the car with eyes open, to tinker with, so in that respect it's been exactly as expected !! Oh, and I have just ordered new HT leads as I have a misfire due to a duff lead - Triggers Broom ???????
 
Last edited:
carnutter5 said:
Thanks for that - apparently anyone who downloads their app gets a 10% discount and its free delivery on top - just waiting for an email back. Battery I was looking at is 130Ah and 1000cca for £90 delivered including the 10% off.

Reference the battery drain - as the key in ignition message goes off, I think the BECM could be going into sleep mode and my issue is a duff battery. It was totally flat when I bought the car so maybe the cold weather has finally finished it off. I am waiting for my Nanocom to arrive, so I will have a play with that as well.

I might just put an Optimate on the car as I only use it at weekends. I have one on my Merc and it has given me piece of mind for the last two years - always topped up when I want to use it.

One way or the other, I am going to get there - I bought the car with eyes open, to tinker with, so in that respect it's been exactly as expected !! Oh, and I have just ordered new HT leads as I have a misfire due to a duff lead - Triggers Broom ???????
Click to expand...
Lead Calcium batteries do not respond well to going flat, often they do not recover.
Get a smart charger from Aldi, £15 and does the same as your expensive branded product, or use a solar panel.:)
 
Hi Guys,
Did "Rick-The-Pick" resolve his wont sleep BECM issue, as I am chasing a very similar issue, wont sleep when lock but sleeps when unlocked.
 
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