RangeRovers.net Forum banner

1 - 20 of 23 Posts

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #1
I’ve had my P38 for a couple of years now and the fob has never worked to unlock/lock the car, but works with blade and starts the engine fine. Seller said it stopped working one day. Red led illuminates when buttons are pressed.
I only have one key so going to bite the bullet and get a new one from LR. Before I do though, is there anything I can check on to make sure the system works first?

thanks
 

·
Super Moderator
Joined
·
2,313 Posts
When you say the LED lights up, does it just light up or does it flash? If just lighting up all the time a button is pressed, it's faulty, if it flashes it's working as it should. Have you tried syncing it? This needs to be done whenever the battery is disconnected anyway and that may be all it needs. Put key in door lock, turn to lock and hold there, while holding in lock position, press and hold the lock button on the fob until the LED flashes faster, release button on the fob and tunr key back to centre. Then turn to unlock, and repeat with the unlock button on the fob, that should sync it. If it doesn't, either the fob is faulty or one of the microswitches in the door latch has failed.
 
  • Like
Reactions: neilfixes

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #3
It blinks when pressed. If i hold buttons down it flashes then flashes faster after a second or two. I've tried syncing in the door. Maybe a faulty microswitch. Guessing i'd need to pull in apart to find out?
 

·
Super Moderator
Joined
·
2,313 Posts
Do the tests here **INFO** Front Door Latch Tests and, if the tests pass, check that the receiver under the RH rear parcel shelf to make sure nobody has disconnected it.
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #5
will give that a go. thanks
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #6
looks like the receiver has been modified. there's a box in-line. Presumably it got upgraded for that wifi issue at some point.

Will plan some time to go thru the microswitch guide...
 

·
Super Moderator
Joined
·
2,313 Posts
The inline box could well be on of Marty's fob filters (P38 RF Receiver Filter) although I didn't think he had them for sale two years ago? I've got one of the first prototypes for testing purposes and that was in July 2018 so they've been on sale now for just 2 years.
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #8
Yes it’s exactly that. I bought it in August 18 so works time wise....
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #9
Door latch tests all complete and passed. Guess that leaves me with a big bill from LR for a new key :-(
 

·
Super Moderator
Joined
·
2,313 Posts
Speak to Marty. There's been odd times when everything seems to be OK yet the fob won't sync so he's been doing a bit of digging into it to see if he can work out why.
 
  • Like
Reactions: j_rov

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,220 Posts
Can you get a picture of the box that appears to be inline with the receiver? If it's one of ours, then I'll be able to identify it.

Also if it is plugged inline, then try unplugging it and plugging the receiver in directly and then seeing if the key will sync. I've had the random occasional feedback that with the RF filter inline the key hasn't been able to sync, but then if it's plugged back in once the key is synced, then it all works as expected. If it's a really early RF filter, then it could be a pre-updated version as we found again in a few small cases on the first ones that the timing was off, so we modified the board and the code to make it more robust.

If it's not one of our RF filters, then it could be a rf controlled relay, as a number of people have fitted them aswell to turn the power on/off to the receiver to disable it/prevent battery drain. Though I would expect you to have another fob on the key chain to activate that aswell.

Also worth checking the key batteries Due to the arrangement of the contacts, it is possible for one of the batteries to be shorted across, so you only get 3V going into the fob, not 6V. I've seen it before where pressing the button will cause the LED to light, but the rest of the fob to not do anything - as the LED will run on the lower voltage, but the rest of the circuitry won't.

Drop me a pic of the mystery box and then also try syncing the key without it plugged in as let me know the result...
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #12
Thanks, will check later on.

I have just sat in the car for an hour waiting for my wife and noticed the doors lock and unlock on their own...
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,220 Posts
Did you notice if one of the front doors WASN'T locking/unlocking with the rest?

I would hazard a guess that the RHF door latch is going intermittent... or more precisely the CDL switch in it.
If you run the latch tests again at some point, do it this time with the multimeter on ohms and see what resistance the CDL switch has. It should be close on nothing, but I've seen them where it's up around 100-200 ohms, which can give bad readings to the BECM. Also try wiggling the sill locking lever to see if the switch drops out easily or not. If it does, then it's definitely a sign that the switch contacts are on the way out.

That may or may not have any bearing on the sync issue... it does use the CDL switch to detect locked/unlocked whilst syncing, but there could be other things going on too.
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #14
Hi, thanks for the help. Will post a picture of the RF device later, however i ran the tests in Ohms mode the first time. The CDL switch was 0.3ohms.

Will try your other suggestions when i can get it all apart again. One thing i did note was a buzz from the passenger size door latch this morning while cranking to start the engine. It went away once engine was running.
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #15
I’ve upset it... battery going flat overnight..... lost sound in front doors (both)

based on what I’ve done above any ideas where I should look first?
 

·
Super Moderator
Joined
·
2,313 Posts
Loss of sound from the front doors would tie in with the other faults. You obviously have the High Line audio (but pre-DSP) with door amps and the ones in the front doors are powered from Fuse 9 via the front door outstations (which you weren't able to connect to). Buzzing from inside the door could have been the central locking motor running so if that was permanently powered that would explain the flat battery. Check power from Fuse 9 and pull a door panel and check that it is getting to the door outstation (pin 10 on the connector).
 

·
Registered
2000 P38 4.6 HSE
Joined
·
64 Posts
Discussion Starter #17
Thanks again Richard. So why would the door motor be permanently running? Would a new latch fix this?
 

·
Super Moderator
Joined
·
2,313 Posts
Dunno, but I have heard of it before. On one of mine if the battery is very low, one of the rear doors tries to lock but sounds as though it is constantly locking and unlocking. I suspect it's down to the same dodgy connection causing the other problems meaning low voltage is arriving there.
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,220 Posts
Yes, that's one of our fob filters. If that's plugged in and you are having battery drain still, then it's got to be somewhere else in the vehicle.

If you can sync the fob without the filter connected, then chances are that filter is one of the very early ones. I've sent you a PM about it.

I'd suggest hooking up a multimeter or a DC amp clamp and seeing what the current drain is that you have - I know of a few common places where battery drain can occur from if it isn't RF - the RHF latch being one of them (usually presents as about a 500mA constant draw, even with the BECM asleep).

I'd try and do a bit more investigation on it to narrow down where the draw is coming from and then go from there. I think a new RHF latch will be in your future at some point anyway if it's been randomly locking/unlocking itself...
 
1 - 20 of 23 Posts
Top