Andy Burrell said:
I disconnected the RF receiver, just locking it with the key which works fine so don't quite understand how it can be picking up anything . Got a fairly new Varta battery too.
Click to expand...
When you say you disconnected the RF receiver, do you mean completely? If the RF interference is strong enough, it's quite possible for just the wire to the BECM to pick something up, unlikely, but possible.
I have not had good experiences with VARTA batteries.
The alternator can flatten the battery, if the "Key in Ignition" switch in the ignition barrel is not working, that can also flatten the battery.
 
Datatek said:
When you say you disconnected the RF receiver, do you mean completely? If the RF interference is strong enough, it's quite possible for just the wire to the BECM to pick something up, unlikely, but possible.
I have not had good experiences with VARTA batteries.
The alternator can flatten the battery, if the "Key in Ignition" switch in the ignition barrel is not working, that can also flatten the battery.
Click to expand...
Yep totally unplugged. The car is about a metre from where our router is in the house office/study and the same distance from a WiFi cctv camera and our cordless phone base stn. If its on the hard standing it's about 20 metres from anything wireless based. I normally buy Yuasa batteries but at the time I needed it the Varta was available next day.
Thanks for the tip about the ignition barrel it's worth a look.
 
I agree with Keith, I had an issue with my old alternator 6 or 7 years ago. After I replaced it things were much better. With the old alternator if I turned the ignition on and left it on for 5 minutes or so I would get the old beep and “alternator fault” would appear on the message centre.
 
Andy Burrell said:
Yep totally unplugged. The car is about a metre from where our router is in the house office/study and the same distance from a WiFi cctv camera and our cordless phone base stn. If its on the hard standing it's about 20 metres from anything wireless based. I normally buy Yuasa batteries but at the time I needed it the Varta was available next day.
Thanks for the tip about the ignition barrel it's worth a look.
Click to expand...
JLR warn that even mobile phones can cause problems. Any piece of wire can act as an aerial if the signal is strong enough and there is very little protection in the P38 wiring or the BECM to stop stray signals interfering. All of that stuff you mention plus wireless door bells can cause problems.
 
If stray RF is waking up the BECM with RF Receiver totally disconnected, then the stray signal must be seriously strong, or something else is causing the drain. Best to do the BECM Sleep checks while you have the receiver disconnected, plus check the battery current if & when it sleeps. See attached for all the things that can "wake up" the BECM.

FYI Before I got Marty's Filter, mine would wake up at home regularly. With just the antenna wire disconnected, it stopped the issue even though I have loads of WiFi, neighbours doorbells, other stray 433Mhz and two mobile phone towers nearby. Verified with a spectrum analyser & oscilloscope !! Conclusion was nothing getting into the wiring loom, except stuff triggering the RF receiver.

upload_2022-7-24_12-10-36.png
 
Andy Burrell said:
I disconnected the RF receiver, just locking it with the key which works fine so don't quite understand how it can be picking up anything . Got a fairly new Varta battery too.
Click to expand...

Did you disconnect the aerial or the power? Unplugging the antenna reduces its pickup range but if a wireless weather station or similar is nearby it will still trigger it and in my case burn your locks out. With no power you cannot use the fob, even holding it by the receiver.

In my opinion unplugging the RF is not a fix - it certainly didn't stop my locks burning out or my battery drain.

A gen 3 receiver fixed mine. Marty's filter should do the same. The cheapest fix is Brian's second fob to trigger a jog switch to isolate the RF receiver.
 
Grrrrrr said:
Did you disconnect the aerial or the power? Unplugging the antenna reduces its pickup range but if a wireless weather station or similar is nearby it will still trigger it and in my case burn your locks out. With no power you cannot use the fob, even holding it by the receiver.

In my opinion unplugging the RF is not a fix - it certainly didn't stop my locks burning out or my battery drain.

A gen 3 receiver fixed mine. Marty's filter should do the same. The cheapest fix is Brian's second fob to trigger a jog switch to isolate the RF receiver.
Click to expand...

I have totally disconnected it and its sitting on a shelf in my workshop. Using the key to unlock which isn't to much of a pain.
Not seen the jog switch option is there a link to it?
 
Andy Burrell said:
I have totally disconnected it and its sitting on a shelf in my workshop. Using the key to unlock which isn't to much of a pain.
Not seen the jog switch option is there a link to it?
Click to expand...

@brianp38dse has posted a link if you search his threads. We ought to put it in the Technical Section.
 
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