Thread: battery drain

Originally Posted by Eevo

following on from this thread
how to change battery, anything special required?

i replaced the battery on sunday, battery was at 12.6volts
its now tuesday, with no driving and the battery is down to 12.1volts.

to save me some time, is there any common battery drains on the p38?

Yep. RFI (particularly 433MHz signals) keeps the BECM awake, you'll need either a Faraday cage for the truck or a permanent trickle charger.

Originally Posted by bee utey

Yep. RFI (particularly 433MHz signals) keeps the BECM awake, you'll need either a Faraday cage for the truck or a permanent trickle charger.

so the BECM keeps getting a 433MHz signal (from somewhere other than the remote), which the BECM keeps trying to decode, keeping it awake???

trying to work out why this hasn't happened in the first 2 months of ownership

If it is the rf receiver could be that someone in your street or nearby has purchased something......mine was going completely flat in 3 days. I would disconnect the rf receiver from behind the rear seat drivers side and see if that makes any difference......you'll soon know.

well after cutting 3 knuckles, breaking 2 clips and cracking the panel, i finally got the rf receiver disconnected.

i also think i found the source of the 433MHz interference.
i recently put new batteries in my weather station, which runs on, yep, you guessed it, 433MHz!

Well found I wish I had been a member of a forum when the specialists cost me batteries and $$$$$$$$ years ago. If you get your fob working you will need to hold it near the back window to work. Also do get the fob working as using the key only is. A time bomb if it fails......and at some stage it will.

Originally Posted by daf11e

Also do get the fob working as using the key only is. A time bomb if it fails......and at some stage it will.

why is it a time bomb?

what cant i do with the key only?

You can do everything with the key no worries...I was told once on RRNet that these were made to use the key as a back up and not daily use as the keys do fail from wear etc....I used my key only for years and one day it broke...luckily my remote worked ok with a set of batteries and unlocked the car. Just from some of the bad stories of keys malfunctioning I've read thought I would pass it on......jfyi.

Do you have an OBD dongle plugged in permanently?

Steve