key remote not working
 

ok, so about 2 weeks ago the key remote on my normal use key (backup key has been dead since I bought the vehicle) stopped working. well, every now and then if I just press the key and keep it pressed while standing next to the vehicle, it will unlock or lock. I was thinking the battery finally wore out in it. it is an 01 x5 after all. battery is like 16 years old as this point.

I looked at videos on youtube about battery replacement and so I took backup remote since I knew its battery was dead and cut it open and replaced it with a brand new non-rechargable battery (there's several videos where people do this actually). I can still manually lock/unlock the vechicle and start it with this key but even with the new battery in it, the remote features dont work.

is it because this one has been dead for so long that the chip wont transpond or should I just buy a new oem battery for it. I will say that I dont have it sautered in place, just sitting in the electronic portion of the key. but I even had this section just sitting in my hand and using one hand to press it together for good contact while using the other one to press the buttons, got nothing.

I hear people talking about some sort of radio antenna in the cars that will go bad and stop the remotes from working but...if this went bad, wouldnt the radio itself have bad reception?

just trying to get this sorted out before we have our first child next month as it will be a pain in the ass to manually lock/unlock the vehicle in july heat with a baby in a carseat lol.

Did you try to sync the key fob that had battery replacement?

I did, but used the 5 clicks on/off method I found on here somewhere for when you dont have a working keyfob...because my working one is now not working.

but even before I opened it up to replace the battery I did confirm that it would still manually operate the locks and crank the car, which it did, which leads me to believe it is still sync'd to the car?

or maybe not?

edit: just for sake of argument I tested two replacement 2025 batteries I bought (in case they were DOA) in a calculator and they do work fine.

one of the videos showing a regular 2025 battery working.
https://www.youtube.com/watch?v=lK7vhXwA0JQ

Although the radio antennas and amps that boosts and sends that data to the audio system are in close proximity to each other...they do run to their respective modules. So one doesn't necessarily depend on the other to operate.

The FBZV & DWA (remote central locking & anti-theft alarm siren) systems do not use a "transponder". The remote key transmits a 315 MHz radio signal which is picked up by the antenna in the rear left cargo window...then sends that data to a receiver in the tailgate. From there...the data is sent up to the GM where the GM sends a command to FZV (central locking) to lock/unlock the vehicle...and to DWA (alarm siren system) to arm/disarm the vehicle.

Both of these systems (FZV & DWA) are independent but work in conjunction with each other. The EWS system is also independent of these two systems and it is the one that uses the transponder in the key. And it does NOT require the battery inside the key...it uses induction to self power itself.

If your remote key is sending the correct RF (radio frequency) for your location (315 MHz in No America...433 Mhz in Europe)...the issue could be some other component that is responsible for getting the command to the GM to lock/unlock & arm/disarm the vehicle.

The Touring (wagon), and SAV/SUVs use a similar antenna set-up...you can see the FZV antenna in the left rear cargo window in the illustration of an e39 Touring below. The FZV antenna for your e53 is in the same location:


You can see in the illustration below of the P-bus...were the GM is the main control module for that bus...and that FBZV & DWA receives their comands from the GM:


The info below shows the e53's remote key receiver and amp which is located in the upper part of the tailgate:

so if I read all that right, the only thing that could feasibly be wrong would be the FZV module in the back left corner? as it simply relays the signal but doesnt care if its sync'd with the car. the sync signal is determined by the GM module...and I'd probably have much larger issues if that was wrong.

or is this thing in the top of the tailgate at the hinge?

edit: went and checked, its definitely up there. I wonder if this needs programming to the car or if you can just swap it out for another one. there's an 06 in the u-pull I might check tomorrow. heading to realoem to see if an 01 and 06 have the same part number lol.

edit 2: it is the same part number and apparently there is one that supercedes it which goes all the way to 2014. either way I'm probably going to go snag it tomorrow. even if its not the issue, once I figure out the issue I can then test the one I pulled and sell it on ebay.

Keep us updated I have been having the same issue with my X5. I even bought a new key and it still wont work

I'm glad I had all my windows down when I did this lol. I was quickly reminded just how loud the factory theft siren really is.

so I grabbed the module from the x5 at the u-pull for $8 and yesterday afternoon decided to change my oil and then goof with this. popped the panel off the hatch lid and then pulled my old module and swapped in the one from the u-pull.

hit the remote and the doors unlocked. nice! then I hit the lock button to test that out and all the doors locked and the car immediately went into lockdown and started screaming at me lol. soo loud. key stopped responding and I could not get the doors open. pulled the plug off the siren and then went and got a ladder and climbed into the car (I'm only 5'8") and cranked it up. finally got it to stop screaming (or so I thought) and turned it off, hooked the siren back up. hit the key again and it started screaming at me again :yawn: :rolleyes:

got it to stop screaming a bit faster this time as I had the driver door open and then swapped the modules back out for the original. hit the key and it started screaming at me again lol. cranked it up and put it in gear and drove about 10 feet and it stopped screaming at me and went out of alarm mode finally. hooked up the siren and wound up the windows and called it a night as the sun was going down and I was deaf.

I'm wondering if the module truly is coded to the system itself instead of just a "code catcher" as referenced above? If I have time this afternoon I'm going to swap them again and put it in drive and see if that resets the system like it did when I put my original module in.

either way, when I initially swapped them, before it started screaming at me, the key did immediately respond and unlocked the car so at least I know the key itself isnt truly dead.

When you have everything buttoned up...when you first arm the vehicle...look at the DWA red status LED to see what it is telling you.

If it is flashing rapidly for the 1st 10 seconds...you may have an open monitor. BTW, it takes approx 20 seconds for the IMS (interior motion sensor) to arm after locking the vehicle. This allows anything that may still be moving inside the vehicle to settle down before the IMS does it thing.

Also, if you had the windows down when you armed (& locked) the vehicle....as you walked/moved by the vehicle...this can set-off the IMS (see info below about the IMS).

And make sure that the driver's door lock cylinder is lubed up...you mentioned that you had to crawl into the vehicle. The driver's door lock cylinder has a MANUAL unlock position that should work regardless if the car has power or has been locked electronically using the remote key. Again, if it is not allowing you to turn 90° counter clockwise...then spray some lube into the lock cylinder and let it "marinate" a few minutes...then make sure that it can turn to the manual UNLOCK position.

ok, either when the alarm went off it burned out the other FZV antenna or that wasnt what the issue was as I swapped them back out and nothing changed.

I went to the car. wound the drivers side window down and popped the hood and unhooked the siren. then swapped the units and got in the car and cranked it up and moved it 10 feet or so. then goofed with the locks. nothing.

hooked everything back up and wound up the window and goofed some more. nothing. its like I never changed it out at this point.

back to the drawing board I guess.

Hmmmm... I'm going to ponder over this one for a while... I'm too tired to think about it right now... Worked last night... I pulled a few things off a 2004 out at the Charlotte LKQ yard... I should have grabbed the valve body from the trans, but I wasn't thinking! It was hot!

Cheers!!!