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LEGACY VENDOR
1995-2002 Range Rover P38A
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Discussion Starter #1
Finally available, after a lot of design and testing! We are happy to say that there is now another option to help solve the problem of RF interference and battery drain that has plauged P38 Range Rovers for going on 20 years now.

We have found a way to filter out all RF transmissions EXCEPT for a P38 key fob. This means that any stray RF which is picked up by the receiver is blocked from waking the BECM up, and thus causing excessive battery drain. ONLY if the filter detects a P38 key fob will it wake the BECM up to then have it check to make sure the fob is valid for that vehicle, and if it is will allow locking/unlocking.

This unit is a 'plug and play' solution - where it connects inline to the RF receiver in the vehicle - which means that you don't need to replace this aswell.

RF Filter.jpg


This has been designed by myself and a fellow P38 owner - Nick, and after a fair bit of testing - including a prototype which went to an owner who was getting all sorts of random messaged about alarm triggered/ignition tamper and a flat battery in a couple of days, caused by a faulty central heating thermostat. After fitting the filter, the owner was pleased to come back and report that there were now no weird messages on the dash and a vehicle which started on the first turn of the key again.

We have even noticed that keys seem to stay synced to the vehicle better in areas of high RF, as not having the BECM constantly checking transmissions means the rolling code doesn't keep advancing to the point where when you come back to use the key, and find it's then out of sync.

Nick has also kindly done a video which is available to watch on youtube (link below) which shows some of the various issues with RF interference, what can cause it, and also with the filter installed, showing it working.

https://www.youtube.com/watch?v=1sROLvILE6k&t=333s

The filter can currently only be ordered via my website - the link is in my signature, and we have tried to keep the cost down - it is currently about a third the price of the officral Land Rover 3rd Gen receiver (YWY500170 for the 433mhz version).

As a side note - this is a completely self-designed unit - we have NOT reverse engineered a 3rd Gen receiver, as the microprocessor chip on these receivers which does the decoding is locked from even being able to read any information from it - so we have had to start from scratch to design and build our own solution.

If this would be better in the 'For Sale' section, then my apologies - let me know and I will post it there, or if an admin can move it!

Cheers,
Marty
 
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1995-2002 Range Rover P38A
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Ordered 1 arrived yesterday but I was out so collected it today (Marty’s post was dec26 I ordered same day and it technically arrived 2 days later darned good service from him and Royal Mail. As the off side rear trim Is off anyway trying to retrieve a dog guard dzuz fastener it literally took 25 seconds to unplug the cable from the rf receiver plug it into Marty’s unit and the lead from that unit to the receiver. We’ll see how I and the car get on
 

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1995-2002 Range Rover P38A
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419 Posts
I would like to buy one, does it come ready for US use?
 

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As it is filtering the code from the receiver rather than the actual RF signal, it will work with a US 315 MHz keyfob just the same as a rest of world 433 MHz fob. I've had a prototype on test for a few months now and can confirm that it works perfectly.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,220 Posts
Discussion Starter #6
Cheers guys.

As mentioned, yes it will work in countries with 315mhz receivers, as it is working on the data stream from the receiver to the BECM and plugs inline.

We have had a couple of component niggles from suppliers, but that seems to be figured out now too - so fingers crossed all continues to be well with them. I think there are about 20 out in vehicles at the moment!
 

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1995-2002 Range Rover P38A
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Hi Guys,

back in Feb 2013 I replaced my receiver on our Gems 1996 4.0 with the new one part# YWY500170 I got directly from Island 4x4 (190 squids, ouch!)

most of the battery problems are gone, none the less the final solution was when I replaced the smallish bosh S4 with the biggest Optima I could fit (yellow version)

I was reading the description of the filter and is it my understanding that this would be redundant for the last gen. receiver?

I am asking as sometimes I have the feeling the BECM is still waking up every now and then (expecially since I got neighbours with a Discovery 3/4)
 

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I was reading the description of the filter and is it my understanding that this would be redundant for the last gen. receiver?
Yes that is correct. The 1st and 2nd gen receivers simply sent the received code through to the BeCM so it woke up, the 3rd gen receiver filters out anything other than a genuine P38 fob signal and only sends that to the BeCM, ignoring all the other transmissions from multitudes of 433 MHz sources. Marty's filter does the same thing, it sees the code from the receiver but only allows a valid P38 fob code through to the BeCM, it blocks everything else. So if you already have the 3rd gen receiver the filter isn't needed.

The best battery you can get for a P38 (in the UK anyway) is the Hankook MF31-1000 ( https://www.batterymegastore.co.uk/hankook-mf31-1000.html). Fits perfectly and will spin the engine over faster than ever before.
 

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1995-2002 Range Rover P38A
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As Richard_G says - if you have the third gen receiver then our filter won't be of any benefit. And the MF31-1000 is a beast of a battery and can't be beat for value/performance in the UK. Have them on both my P38s.

If your P38 is still waking up, something else is causing it. Best thing to do first is confirm if it is actually waking up.
 

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1995-2002 Range Rover P38A
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As Richard_G says - if you have the third gen receiver then our filter won't be of any benefit. And the MF31-1000 is a beast of a battery and can't be beat for value/performance in the UK. Have them on both my P38s.

If your P38 is still waking up, something else is causing it. Best thing to do first is confirm if it is actually waking up.
Thanks for the Tip RE-Battery, I will remember next time.

I am not sure if it is waking up, mine is just a guess.

My car is OK, most of the electrics work (everything exeptr the two heated seats and the passenger flood light) , but I am just getting the "odd-once-a-quarter" <alarm fault> and sometimes I have the impression the battery is lower than usual; havin said that , then I am using the car for short trips (3-4 miles tops) 3-5 times a week , so that could explain the whole thing.

It could also be that the Alternator is not in "top health", I am no sure how long they last, mine is over 125K miles, so might be needing of some TLC.

I am keeping an eye on the whole thing.... preventive maintenance is important but sometimes is like chasing a wild goose , basically for some issues you need just to wait until a permanent fault occurs.

BTW, I need to do my lyning, most likely the alarm falt could be because the whole thing is falling.
 

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Alarm fault can usually be cured by unplugging the ultrasonic sensor above the B post and giving the connector a blast of contact cleaner. Heated seats rarely work, people keep sitting on them and breaking the elements......
 
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LEGACY VENDOR
1995-2002 Range Rover P38A
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Discussion Starter #13
That's pretty much covered it all... !

In testing, we did try linking our filter after a gen3 receiver - and it does still work, but there's a bit of a noticable delay in the vehicle responding. We looked at it and it's because there's a slight delay between the gen 3 receiver getting the data and sending it back out, whilst it's processing. Our filter has a similar delay, which when in line with the gen 3 receiver becomes noticable when you press the key. So we actually don't recommend using the filter with the gen 3 receiver.

Best results we have seen is with the gen 2 receiver as it has better frequency filtering than the 1st version - but it will work with either.

As mentioned, alarm fault is commonly the ultrasonic sensor - either the sensor itself fails (it's actually the same part as a Disco sensor from memory) and I've found on a couple of occasions either dirty connector as Richard_G mentions, or even corrosion in the connection - one time one of the pins had corroded and snapped, so I ended up having to put a new pin on the wiring loom.
 

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1995-2002 Range Rover P38A
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Great , thanks for all the replyes and tips

I still have the GEN1 RF receiver in my "P38 spares box" , I will keep it just in case the other fails, knowing I can use it with the filter .

:mrgreen:
 

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Finally available, after a lot of design and testing! We are happy to say that there is now another option to help solve the problem of RF interference and battery drain that has plauged P38 Range Rovers for going on 20 years now.

We have found a way to filter out all RF transmissions EXCEPT for a P38 key fob. This means that any stray RF which is picked up by the receiver is blocked from waking the BECM up, and thus causing excessive battery drain. ONLY if the filter detects a P38 key fob will it wake the BECM up to then have it check to make sure the fob is valid for that vehicle, and if it is will allow locking/unlocking.

This unit is a 'plug and play' solution - where it connects inline to the RF receiver in the vehicle - which means that you don't need to replace this aswell.

View attachment 269136


This has been designed by myself and a fellow P38 owner - Nick, and after a fair bit of testing - including a prototype which went to an owner who was getting all sorts of random messaged about alarm triggered/ignition tamper and a flat battery in a couple of days, caused by a faulty central heating thermostat. After fitting the filter, the owner was pleased to come back and report that there were now no weird messages on the dash and a vehicle which started on the first turn of the key again.

We have even noticed that keys seem to stay synced to the vehicle better in areas of high RF, as not having the BECM constantly checking transmissions means the rolling code doesn't keep advancing to the point where when you come back to use the key, and find it's then out of sync.

Nick has also kindly done a video which is available to watch on youtube (link below) which shows some of the various issues with RF interference, what can cause it, and also with the filter installed, showing it working.


The filter can currently only be ordered via my website - the link is in my signature, and we have tried to keep the cost down - it is currently about a third the price of the officral Land Rover 3rd Gen receiver (YWY500170 for the 433mhz version).

As a side note - this is a completely self-designed unit - we have NOT reverse engineered a 3rd Gen receiver, as the microprocessor chip on these receivers which does the decoding is locked from even being able to read any information from it - so we have had to start from scratch to design and build our own solution.

If this would be better in the 'For Sale' section, then my apologies - let me know and I will post it there, or if an admin can move it!

Cheers,
Marty
Hi Marty, I’m looking to purchase a plug n play P38 fob filter but cannot access the web page. Can you help please? Regards, Des
 

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P38 RF Filter should take you straight to it, although it's shown as out of stock at the moment. This might be because Marty's work takes him all over the planet so there might be a delay if he isn't at home. Better to show it as out of stock than have people placing orders when he's nowhere near home to post it out.
 

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P38 RF Filter should take you straight to it, although it's shown as out of stock at the moment. This might be because Marty's work takes him all over the planet so there might be a delay if he isn't at home. Better to show it as out of stock than have people placing orders when he's nowhere near home to post it out.
Found it! Thank you very much.
 

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1995-2002 Range Rover P38A
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Hi guys,

I work with Marty producing these - we hope to have them available again in a couple of weeks :)
 

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Off topic,
but can anyone on here point me in the direction of where to buy a new or reconditioned switchpack for the electric windows on my P38
?
many thanks
 

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Same place, Marty
 
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