P38 RF Receiver to BECM

dubloman said:

Hi

I am unsure if anyone has asked this question as I have spent most of the afternoon looking but cannot find what I need.

The problem I have is this

The RF receiver (green dot) seems to have failed. I know that it has the blue antenna wire and the three-wire plug (Purple, Black & Red/Orange) but I don't know where these wires go to on the BECM
The 3 wires are Earth, Signal and 12 volt positive feed.

If I use a multi-meter on continuity and test the Blue and the black (I assume signal in and out) I get tone, I don't know what the other wires are for (I hope someone can tell me)
The blue is the aerial wire.

If I use a blue dot the key will sync and work for a few days, then fail but then I am back to square one.
That tends to indicate the wiring is OK, but it's worth checking for corrosion on the connectors at the BECM. You can identify the connector you need from RAVE. Check also for dampness under the carpet in the drivers footwell.

I cannot find where the RF receiver will plug into the BECM so I cannot check the continuity of the wires between the RF receiver to the BECM as I feel that it is either a problem with the BECM or the wires between the two points, if you know what plug and colour the wires are at the BECM then that would be helpful.

Does anyone know how to test the RF receiver off the car and how common is it for them to fail. If I have continuity between the Blue and black does this mean that the signal will come in and go out, is it also possible that the BECM is at fault or is it just the RF Receiver or is it the wires and how common is this fault
Easy to do a rough check of the receiver in you have an oscilloscope, but they rarely fail although the early ones as you are aware suffer from interference. Continuity between the blue & the black means nothing. Loosing sync or failing to work can be due to other things such as the micro switches in the drivers door lock and the shutter in the ignition barrel.

If the RF receiver has failed who (if anyone does it) can repair the RF receiver as the green dots are 200 plus 2nd hand and the blue dots with all the problems are still 35 plus 2nd hand.
It's unlikely the receiver has failed.

I apologie if this subject has been done to death but the questions I have asked I cannot find the answers on this forum or on the Rave program or electrical version of the same and that is why I am asking this forum and all the knowledge that members have.

Thanks in advance for all the info

Dave

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dubloman said:

Hi

I am unsure if anyone has asked this question as I have spent most of the afternoon looking but cannot find what I need.

The problem I have is this

The RF receiver (green dot) seems to have failed. I know that it has the blue antenna wire and the three-wire plug (Purple, Black & Red/Orange) but I don't know where these wires go to on the BECM

If I use a multi-meter on continuity and test the Blue and the black (I assume signal in and out) I get tone, I don't know what the other wires are for (I hope someone can tell me)

If I use a blue dot the key will sync and work for a few days, then fail but then I am back to square one.

I cannot find where the RF receiver will plug into the BECM so I cannot check the continuity of the wires between the RF receiver to the BECM as I feel that it is either a problem with the BECM or the wires between the two points, if you know what plug and colour the wires are at the BECM then that would be helpful.

Does anyone know how to test the RF receiver off the car and how common is it for them to fail. If I have continuity between the Blue and black does this mean that the signal will come in and go out, is it also possible that the BECM is at fault or is it just the RF Receiver or is it the wires and how common is this fault

If the RF receiver has failed who (if anyone does it) can repair the RF receiver as the green dots are 200 plus 2nd hand and the blue dots with all the problems are still 35 plus 2nd hand.

I apologie if this subject has been done to death but the questions I have asked I cannot find the answers on this forum or on the Rave program or electrical version of the same and that is why I am asking this forum and all the knowledge that members have.

Thanks in advance for all the info

Dave

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Grrrrrr said:

Something like a Nanocom will tell you if the BECM received a valid code. If it doesn't then working out what failed will be a bit of detective work. Have you got RAVE? That has all the wiring diagrams so will tell you what power to expect where. @martyuk is a bit of an electrical whizz but not sure if he's around at the moment.

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Datatek said:

Unless you can delete the last valid code received before you operate the FOB, it will not confirm receipt of a valid code.

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dubloman said:

Hi

Thanks for your replies as I do appreciate your swift replies.

I do have RAVE but can you tell me what section and page the wiring diagram would be on (so I can check the plug and clean as needed)

The vehicle did have water getting into the drivers footwell and after I sorted out the sponges on the valance (The car is new to me, only owned it a few months) It is now dry but might have had condensation on the plugs etc.

I do have a BECM kit (ignition and door lock etc) so if I can get the alarm turned off I can change the BECM if that is the problem

Thanks

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dubloman said:

The kit contains the following
BECM
2 key fobs matched to the BECM
Ignition switch
Door Lock
Instrument Binacle
EKA code and chassis number & Reg of the donor vehicle.
I hope that helps clear that up

I have had lots of posts and lots more info on this subject and I thank everyone for their input.
I still don't know and can not find the page on RAVE that says what plug controls the signal from the RF receiver so that would be useful please
I can remove the BECM and dry it out as suggested (take the top off and apply gentle hot air) and clean all the plugs to try to rule out that element.
The nanocom has been suggested, I assume it is the Nanocom Evolution and can this remove the fob memory as suggested and can it sync the becm to the ecu if I put the new becm into the vehicle.

This is my next big question, I am in Preston Lancashire and have been on the spanners for many years and am a old school MOT tester, I became ill some years ago and all my tools were stolen, I am new to the nanocom devices but have used other plug in units years ago (yes they have become much more advanced) but the big question is this
Is there anyone in my area who is prepared to lend me one of the units (I can leave the wife as a deposit....lol......Or if that's a problem cash as a deposit) but I could do with either buying one or asking someone to kindly lend me a unit if they will do all the jobs that I clearly need to do
If it works for a short time then stops what would be the cause of an intermittant fault?

Thanks again
Dave

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Datatek said:

Personally, I would not even consider swapping out the BECM for what is most likely a minor problem, it should be a last resort. As I said, a dodgy drivers door lock/micro switches can cause exactly the problem you have, indeed I have just sorted the same problem on my project P38.

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Grrrrrr said:

+1.

There's a man near Preston that knows more about the P38 with the M51 engine that all of us put together. Now, what was his nickname? Hammer or something?

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Datatek said:

But his mobility scooter won't go that far on one charge

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wammers said:

I'll have you know it has a 25 miles range.

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