Electrical Failure

tomcat59alan said:

There are three versions fitted to the P38, there has been a photo of the innards posted on here. Unscrupilous sellers will change the spot.

Click to expand...

Too true. The latest has 2 boards at right-angles to each other inside instead of a single board. Brian's 12V remote switch is the way to go until Land Rover stop taking the pss on prices.

Grrrrrr said:

Too true. The latest has 2 boards at right-angles to each other inside instead of a single board. Brian's 12V remote switch is the way to go until Land Rover stop taking the pss on prices.

Click to expand...

Yup, worked for me.

And me

I doubt they will stop taking the **** on prices sadly...
I have a feeling there is a new '3rd gen' (part number still the same) with a PCB redesign so it's all on one board again now, rather than having the one sticking up - I seem to remember someone on RR.net putting a photo of it up. I think LR ran out of the 'original' 3rd gen receivers and ended up getting another production run done, but they must have tidied the board design up a bit... they still work in the same way...

I think I've identified that the preamble on all the P38 fobs is the same, so if anyone is good at RF and can use that as an 'activation' for the RF receiver (which I am guessing is what LR have done - made is so the RF receiver ONLY wakes the BECM up when this is detected, rather than on any transmission at all) then drop me a message, and I'm happy to collaborate to try and see if there's a way to modify the original receivers, as I'm guessing it's only a few ££ in parts that is different, but LR are making stupid markup on...

Well, thanks to brianp38dse, I decided to recheck the Alternator output.
Engine running 14.3 volts, switched on headlights, front and rear screen heaters, blowers etc, 13.8 volts.
After a few minutes dropped to 12 volts and then rapidly dropped off to 8 volts !!!!
Turned engine off and left it for an hour, started and checked Alternator output.......nothing!!!!!!
Looks like the Alternator output was intermittent thus giving me the odd behaviour.
Just checked it again and the Alternator is doing nothing, must have finished it off with the high loading.
Will replace the Alternator and hopefully that will be the end of this saga.
Thanks again Brian

tony2 said:

Well, thanks to brianp38dse, I decided to recheck the Alternator output.
Engine running 14.3 volts, switched on headlights, front and rear screen heaters, blowers etc, 13.8 volts.
After a few minutes dropped to 12 volts and then rapidly dropped off to 8 volts !!!!
Turned engine off and left it for an hour, started and checked Alternator output.......nothing!!!!!!
Looks like the Alternator output was intermittent thus giving me the odd behaviour.
Just checked it again and the Alternator is doing nothing, must have finished it off with the high loading.
Will replace the Alternator and hopefully that will be the end of this saga.
Thanks again Brian

Click to expand...

He's only repeating what we taught him. Where did you check the alternator output, at the battery or at the alternator?

At the Battery.
All cables removed and checked earlier including the Alternator cables

Try checking at the alternator, see if there is a voltage difference. If there is I would go for an intermitant wiring fault.

More investigation work done today........
Charged battery up overnight and now reading 12.7 volts, nice and healthy.
As you suggested tomcat, checked at the Alternator terminal and reading 12.7 volts also.
Turned on ignition and Alternator Fault came up on the display plus there is no ignition warning light showing. (Hadn't noticed that before)
Measured voltage at W+ terminal on the Alternator at 6.3 volts.
Disconnected W+ cable from the Alternator and measured voltage again, now reading 12.3 volts.
Earthed out W+ cable and Ignition Warning light comes on.
Think I should get another Alternator.

Good used Alternator fitted on Wednesday and all back to normal operation.
Hopefully that is the end of it.
Thanks to all who contributed to the thread

martyuk said:

I doubt they will stop taking the **** on prices sadly...
I have a feeling there is a new '3rd gen' (part number still the same) with a PCB redesign so it's all on one board again now, rather than having the one sticking up - I seem to remember someone on RR.net putting a photo of it up. I think LR ran out of the 'original' 3rd gen receivers and ended up getting another production run done, but they must have tidied the board design up a bit... they still work in the same way...

I think I've identified that the preamble on all the P38 fobs is the same, so if anyone is good at RF and can use that as an 'activation' for the RF receiver (which I am guessing is what LR have done - made is so the RF receiver ONLY wakes the BECM up when this is detected, rather than on any transmission at all) then drop me a message, and I'm happy to collaborate to try and see if there's a way to modify the original receivers, as I'm guessing it's only a few ££ in parts that is different, but LR are making stupid markup on...

Click to expand...

Still a green dot or have they changed that too?

I think I've got an original blue dot receiver in my shed if that would help you?

As far as I know the new ones, even with the PCB revision still carry a green dot, and the same YWY500170 part number, yes. Though if anyone is buying one second hand, then I recommend actually opening the casing and checking to make sure it's genuine as a few unscrupulous eBay sellers have been known to stick a green dot on it and sell it as a 'green dot updated receiver' and it's actually the version 2, not 3 - which is better, but not the solution... and can be had normally for probably £40 ish!

I'll have a look in the garage, but I think I have 3 or 4 different receivers kicking about from various locksets that I've collected over the years!

If I get the chance before I head away for work, then I will be trying to do a capture of fob transmissions from as many P38 fobs as I've got lying around, so I can check to see if what I think is the same preamble across all P38 fobs actually is, then it's a case of working on a way of identifying that and passing the transmission on, or blocking anything that doesn't match. Also working on seeing if I can find anything in the BECM programming that identifies the FOB. I've already managed to work out what most of the 'Coding Data' you can retrieve with the SM035 module is, and how pretty all of the user changeable BECM settings are stored.