how to engage immobiliser, or if I should leave it off

[workingonit]

While I was having trouble with my dead diamond key remote repair, I tried to re-initialize it (unsuccessfully, since there was a loose trace inside the key). The "clowns nose" red light under the rear-view mirror blinked a couple of times, and nothing else happened.

I soldered the loose trace in the key, and it worked fine after that, but I've not seen the red light again. Is the immobiliser off or on? Since I only have the one diamond key (no other key), should I try to engage the immobiliser system or not? The key may malfunction at any time (from the damaged trace inside), and the system may not let me in.

I'm retired, at home 95% of the time, the X5 sits among several other vehicles & trailers in the "car paddock" behind my house (mostly hidden from street view, in my semi-rural area. Guarded by me full-time and my five dogs, it shouldn't be in much danger of theft (we're armed), though it appears to be the prime target among the "stable". Though, if I do drive and park away from home, I'm sure that an alarm may be a nice thing to have.

If the single diamond key will still let me into the X5, even if the remote goes unfunctional again (the embedded RFID chip should still be recognized), then how do I use/engage the immobiliser? I've read the manual, but it's still unclear.

[oldskewel]

There are some people on here who seem to know more than even BMW about how these things work. Until they respond with the answers, some brief clues I can offer are ...

I don't think you're using the term immobilizer as it is usually used. I think of that as the system that uses an RFID chip in the key that is interrogated by the ECU upon starting the engine, and the ECU will either allow start or not.

The keyless entry system is separate, easily programmable by following a sequence of button presses, etc. That allows you to lock/unlock doors, disable the alarm (that would be automatically set when locking), and even roll down windows and open sunroof if holding down the unlock button.

The alarm is separate.

The mechanical key blade is the 4th fairly independent thing in this part of the whole security system.

I believe the clown nose indicates whether the alarm is armed. It is armed automatically when locking the car when the key is out of the ignition, whether done with the mechanical key in the door or with the keyless entry remote. If locking with the mechanical key does not set the alarm, it would indicate some issue somewhere in the whole system. And that is a major factor to consider - the system is pretty complex, and if one part (door lock actuator, for example) has a partial electrical failure, it can make the whole keyless entry and alarm systems inoperable. <== and that's exactly what happened to me.

If you can't get keyless entry to work, and rely on the mechanical key in the door to lock and unlock, you can be sure the lock cylinder will fail within about a year of daily use, leaving you in a predicament. <== and that's exactly what happened to me.

A cheap and easy solution to the need for a remote functionality is to buy a used genuine BMW diamond key on eBay (I bought 3x for $15 each when I got my car). You can then cut the key blades off (useless on your car), reprogram the keyless entry functionality, and use them as key fobs. You'll need to find a convenient way to keep them charged. When you go to start the car, the immobilizer system will see the RFID chip in your actual key as well as the old one in the eBay fob, and will just ignore the eBay one, allowing the car to start. <== All that is exactly what I've been doing since 2014.

[workingonit]

I need two totally functional diamond keys! They both must be recognized by the ECU. If they both have a functional remote, then I should not have to use the failure-prone driver-door-lock any, or maybe occasionally. The clown nose immobilizer/alarm system is secondary to that consideration, to me.

How do you tell what is a $15 "genuine" BMW diamond key on E-bay? Your method to make a "remote only" fob sounds good, at least until I can get a mechanical/remote from a dealer or parts house (i've had bad luck on E-bay). I just want a back-up to my original re-soldered diamond key, before the remote fails again.

I don't trust locksmiths much either, so I'm planning to get a laser-cut mechanical key or full functioning diamond key, ordered thru https://www.thebmwminipartstore.com/ I may get both. I'm assuming that BMW NA laser cuts them prior to sending to the parts dealer.


I'm deadly to plastic key fobs...I break them all. I put a silicone cover on mine after the repair, just to cushion some impacts. I need to carry the diamond key in a hard case, until I get a spare!

[oldskewel]

I did a quick search on eBay, and this is what I mean by a used key:
https://www.ebay.com/itm/12429386604...sAAOSwZtdfMeel
But I'm not sure if the 433 MHz will work for you. For some reason, I think it is 315 MHz. Something to look up somewhere, or maybe somebody else knows that.
I guess 7 years later, the prices have gone up and availability down, vs. what I paid back in 2014.

To go with the 3x eBay used diamond keys, I bought 3x valet keys from thebmwminipartsstore as you listed. Great deal, service, etc. When I got mine, the only options they had were diamond or valet.

Here is a thread about my solution, back when I needed to replace a couple of the batteries. Things still working great there.
https://xoutpost.com/bmw-sav-forums/...r-options.html

[workingonit]

Originally Posted by oldskewel

...You can then cut the key blades off (useless on your car), reprogram the keyless entry functionality, and use them as key fobs. You'll need to find a convenient way to keep them charged...

You can always buy a Philips Sonicare toothbrush charger to keep fob's charged. I did, before the battery (the original, over 20 years old) was replaced, and it would bring it back for awhile after many hours of charging. Now, with a new rechargeable VL2020 battery inside, I just let it charge every couple of days (while not using the BMW).

[plasstik]

that’s a legit to keep the key(s) charge!!


Sent from my iPhone using Xoutpost.com

[upallnight]

the immobilizer is like a wheel lock. it gives you that safe feeling until you lose the tool to unlock the wheel with a flat tire in a shady part of town.

[workingonit]

I finally drove the X5 off my property yesterday, for a total of 11 miles. Good road feel, better than any of my other vehicles (as expected, it's a BMW), and filled the tank with premium (haven't had to use premium since the old Chevelle was still streetable w/11:1 compression, on the first 427 engine).

Automatic climate control A/C worked great, with 40 degree air from the outlets, even on a short, slow drive at 45mph in 98 degree heat. It'll probably get colder on a highway run, so I'm pleased with that.

Engine coolant in the middle of the gauge, good, but I want to get a transmission temperature reading (maybe use my Torque Pro, or OBDLink apps for that, on my Android tablet or phone). Lots more things to explore on another drive, soon.

Bonus from the short drive: the immobiliser is now working. Don't know what fixed it (maybe a pinched wire in the rearview mirror? the only thing I adjusted....). So now I must get the key fob backup, since I don't want to be locked out, or unable to disengage the immobiliser alarm, etc. I'll order a couple of keys from oldskewel's link, today, and try his method.

Another item I'm going to try: an onboard charger/maintainer. I use charger/maintainers on all my other vehicles (and trailers), but I have read of the difficulties of getting in/out of the X5 if the battery was to go flat. The doors seem resistant to locksmith's methods.... So, I'll mount an onboard charger/maintainer (IP65 or 67) underhood (connected to the jumper terminals there, power cord (with a sealed A/C supply cord interface) just inside the kidneys), so I can unlock something after a trickle charge.

I'm already using one (not weatherproof), with it connected thru the cigarette lighter port in the backseat, power cord out the door, but it must be removed and stored in the back; whereas on the other cars/trucks it can be tucked under the manual seats, without possibly interfering with the electric wiring/motors/automatic movement? of the BMW's seats.

[wpoll]

I trickle-charge (or charge) mine via the trailer connector. :-)

[workingonit]

Originally Posted by wpoll

I trickle-charge (or charge) mine via the trailer connector. :-)

My EE friend put on the hitch before we swapped cars. He used the X5 occasionally (usually a Ram pickup, or the Subaru project) to tow his dirt-bike to local sites. He had a 4.5'x12' trailer w/o brakes, so he rigged a 4-way for the lights.

I now own that small trailer (we traded trailers, too), and I have two pickups modded for towing anything, that I can use for my braked trailers, so I probably will take my time installing a proper 7-way (with 12v feed wire) on the X5. Otherwise, your idea of using that to charge the battery would be perfect.