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Alarm system disable '96 P38 HSE 4.6

3296 Views 27 Replies 10 Participants Last post by  jimco1
Gents, Is there an easy way to permanently disable the alarm system while still keeping the key fob entry? This system seems to be a little over kill
for us guys out in the country. Thanks
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No. The alarm and immobiliser system is integrated with the BeCM rather than added on. They are turned on when the car is locked, even if you use the key rather than the fob. The only way to avoid setting the alarm is to not lock the car.
No. The alarm and immobiliser system is integrated with the BeCM rather than added on. They are turned on when the car is locked, even if you use the key rather than the fob. The only way to avoid setting the alarm is to not lock the car.
You bring up an interesting point.....:think:
For those that hate the alarm system (And what's to like?:confused:) You could unlock everything, and just unplug all the door latches. Never will an signal be sent to the Becm to tell it to alarm.....8-0=
Then you install the aftermarket central locking system!
What could possibly go wrong?:pray:

This could actually work, but I would never personally contemplate doing it to either of mine:naughty:

Mind you, if I had a Gems, it would DEFINITELY have a Mobi installed! They rock!:dance:
You bring up an interesting point.....:think:
For those that hate the alarm system (And what's to like?:confused:) You could unlock everything, and just unplug all the door latches. Never will an signal be sent to the Becm to tell it to alarm.....8-0=
Then you install the aftermarket central locking system!
What could possibly go wrong?:pray:

This could actually work, but I would never personally contemplate doing it to either of mine:naughty:

Mind you, if I had a Gems, it would DEFINITELY have a Mobi installed! They rock!:dance:
I have a GEMS and a Mobi, and Lee (from LAB (Mobi)) is working with me to come up with a 3rd party remote start & door lock system since Mobi already bypasses the BECM issue.

Pre Mobi, the PO had a new unlocked BECM installed, and simply disconnected the RF receiver---had to lock the driver's door manually, but no jumping lock issues (knock on wood). I'm simply looking to take that one step further.
You can switch the alarm off in the BECM. The only part of the system you can't switch off is the immobiliser which is implemented by the engine ECU, not the BECM. The BECM just sends the mobilisation code to the engine ECU when the vehicle is unlocked/disarmed and the ignition turned on.

If you have a properly working drivers door latch, and have the alarm and passive immobiliser turned off, then you circumvent most of the issues that people run into. As mentioned above, there is a bypass module for the immobiliser for a GEMS engine ECU - but the Bosch ECU doesn't have a workaround, so at least requires a working door latch to tell the BECM when it's locked/unlocked so it can send the code through.
I think you can disable the alarm with a Nanocom, you can also just pull the alarm horn off, or damage it so it doesn't make noise anymore, that's what I did.
Alarm horn is under the fuse box.
I think you can disable the alarm with a Nanocom, you can also just pull the alarm horn off, or damage it so it doesn't make noise anymore, that's what I did.
Alarm horn is under the fuse box.
Alarm can be disabled electronically yes. removing, disconnecting or otherwise rendering the horn inoperative simply keeps it from making noise, the other elements such as immobilizing, light flashing etc. still remain active, thus by simply rendering horn inactive nothing is accomplished.
I have a GEMS and a Mobi, and Lee (from LAB (Mobi)) is working with me to come up with a 3rd party remote start & door lock system since Mobi already bypasses the BECM issue.

Pre Mobi, the PO had a new unlocked BECM installed, and simply disconnected the RF receiver---had to lock the driver's door manually, but no jumping lock issues (knock on wood). I'm simply looking to take that one step further.
Could you give me a link or more info on this I am trying to find a way around every time I have battery problem my alarm disables my 99 P38 and I have to remove door panel and ground switch to get going again. Nothing else works for me.
You can switch the alarm off in the BECM. The only part of the system you can't switch off is the immobiliser which is implemented by the engine ECU, not the BECM. The BECM just sends the mobilisation code to the engine ECU when the vehicle is unlocked/disarmed and the ignition turned on.

If you have a properly working drivers door latch, and have the alarm and passive immobiliser turned off, then you circumvent most of the issues that people run into. As mentioned above, there is a bypass module for the immobiliser for a GEMS engine ECU - but the Bosch ECU doesn't have a workaround, so at least requires a working door latch to tell the BECM when it's locked/unlocked so it can send the code through.
Are there more info posted that I could look at on doing this.
Could you give me a link or more info on this I am trying to find a way around every time I have battery problem my alarm disables my 99 P38 and I have to remove door panel and ground switch to get going again. Nothing else works for me.
You need to replace the latch then so the microswitch grounds the wire as it was designed to do.
Could you give me a link or more info on this I am trying to find a way around every time I have battery problem my alarm disables my 99 P38 and I have to remove door panel and ground switch to get going again. Nothing else works for me.

What Richard said -- the driver's door latch must have a good connection. It sounds like you have a battery drain issue -- likely due to the RF receiver if it hasn't been updated to one of the later generations. There aren't any great work-arounds on a p38 -- but all the known issues and fixes are well documented. The door latch issue is pretty high up there on the PITA factor, but Rimmer Bros has the latches at 1/10th what they are going for in the US and after you've done one, the next one is < 1 hour work.
You need to replace the latch then so the microswitch grounds the wire as it was designed to do.
I replaced the latch the wiring and the Box inside the door.The only way to unlock the door is the key. When I turn the key clockwise it locks all the doors, when I turn it counterclockwise it unlocks the driver door but also locks the other doors. The remote only locks or unlocks the right door and both back doors. The latch was new from Partsgeek the wiring was bought from ebay I bought 2 sets and used the one I thought matched my burnt wiring. The outbox I think was new but not sure. None of this was a problem to me since I do not mind using the key. The issue is if I let the truck sit for a week or so battery is dead and I have to remove door panel and ground 2 wires to get it going again.
Genuine latch or pattern? Sounds like the latch or the wiring to it is crossed.
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What Richard said -- the driver's door latch must have a good connection. It sounds like you have a battery drain issue -- likely due to the RF receiver if it hasn't been updated to one of the later generations. There aren't any great work-arounds on a p38 -- but all the known issues and fixes are well documented. The door latch issue is pretty high up there on the PITA factor, but Rimmer Bros has the latches at 1/10th what they are going for in the US and after you've done one, the next one is < 1 hour work.
I have tried all the fixes posted replaced all parts in door (I did let bad wiring go to long before replacing it and latch). The only fix that able to get me going again was removing door panel and grounding 2 wires from switch. Will look into updating RF receiver is this a replacement part or software update the closest dealer to me is 200 miles.
OK, so it is working but not quite how it should. Turning the key clockwise on a LHD car is to Lock so it is doing exactly what it should. However, the same thing would happen if you were in the car and pushed the sill locking button down. Difference is that pushing the button down only operates the CDL switch, but not the keyswitch, turning the key should operate both. That would suggest the keyswitch in your new latch isn't working or the wiring is wrong so its operation isn't being recognised. Turning the key counterclockwise will be towards unlock. It mechanically operates the CDL switch by pushing the sill locking button up and that, combined with the keyswitch being operated, should cause the other doors to unlock. It can't lock them as they are already locked?

Using the remote it sounds like it is working as it should, only problem is, you have a faulty drivers door latch or wiring to it so it isn't working as it should. If your car is a 99, it should have the 8 way connector (with only 7 wires used) but if you have fitted a loom (or latch) from an earlier car with the 6 + 1 connectors, it isn't going to work as the wiring is different.

Battery drain caused by local RF is a different matter. You need either the Gen 3 receiver or one of Marty's RF filters (www.p38webshop.co.uk) which does the same job at 1/4 the cost.
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If all the doors are unlocked turning the key either way locks them turning the key clockwise locks all 4 locks. The only way to unlock LHD driver door is to turn key counterclockwise which if the other 3 doors are unlocked it locks them, then I use the remote to unlock them and drive. Do you think I should replace wiring 1st and see what that does or do think I got a bad switch.
If turning the key either way locks the doors, the CDL switch isn't working. The keyswitch is operated when the key is turned, irrespective of which way it is turned, just that it is being turned, it is the CDL switch that tells the door outstation whether the key is being turned to lock or unlock.
If turning the key either way locks the doors, the CDL switch isn't working. The keyswitch is operated when the key is turned, irrespective of which way it is turned, just that it is being turned, it is the CDL switch that tells the door outstation whether the key is being turned to lock or unlock.
I changed the outstation when I redid door do not remember whether it was new or used think any chance it is the problem? The CDL switch is part of the new door switch I replaced correct, I am thinking about replacing wiring and everything in the door again and seeing if this corrects the problems. I can use the truck as it is just have to turn the key to the left to unlock driver door and use remote to disarm truck and unlock other doors and drive, but if I lose power for any reason I have to remove door panel and ground 2 wires and that is a pain. I have tried the contact that was left in this post about RF block but I just get not in stock message.
When you ground the two wires, you are grounding the keyswitch and CDL switch which is what should happen when the key is turned to unlock. If you only ground the keyswitch, without grounding the CDL switch, that is what would happen when the key is turned to lock. Use the sticky at the top of this forum to test the door latch. Even though new you may have got a faulty one. If that tests OK, test again at the plug that goes into the outstation.
Thanks for the info I have ordered another switch and outstation easier for me when I have door panel off to replace these, if these do not fix it guess I have to find another wiring harness for the door. I will report back on what I find once parts get here.
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