I've tried numerous techniques over the past week to program my keyless remote to work, but I'm having no luck. I've even opened up the remote to confirm the hardwired battery is installed and charged. At this point I'm thinking it's the BCM or IR receiver. Is the IR receiver in the rearview mirror in the '07 R52 MCS? What's the usual suspect, BCM or IR receiver if the car won't take programming?

EDIT: Just realized I posted in the wrong area. I'll ask a mod to move.

 

I removed and dismantled the mirror, and the circuit board at the bottom looked fine. I disconnected and reconnect the plug and reinstalled everything. The car still won't take programming. :(

 

You didn't mention what year car & key fob you're using. If you aren't aware of it, you cannot program '04 and earlier keys - that's only for '05 & up. If you do have an older car and key, you would have to visit the dealer and pay them an hour's labor to program it.

 

I have an '07 R52 MCS. I only have one key, and the keyless function hasn't worked since I bought the car a few weeks ago.

 

Is there a possibility that the key that came with the car is one of those worthless E-bay keys? The only key that will work with your car is a factory provided key set to your VIN. To get one of those you HAVE to contact a dealer, provide a copy of your title and DL (copies can be faxed or emailed) and it has to be picked up at the service desk. There's a simple get acquainted procedure you have to do with it in the ignition which the service guy will explain to you.

 

I'm pretty certain it's the real deal. It has typical wear and tear and when I broke it apart it had the same composition as the OEM's. Plus it has the hardwired battery, which isn't replaceable.

I'm starting to suspect the BCM was replaced with a used unit, which would then disable the keyless entry function.

I've attempted the "get acquainted" technique at least 30 times using around 4 variants I've found on YouTube or Google.

 

Sounds like the original/previous owner did an evil deed.

 

It's possible the receiver isn't working, and it's the easiest thing to investigate further. Unfortunately that receiver isn't available separately (only included with a complete mirror assembly). Also see if it makes any difference if you hold the key next to the mirror while attempting to program. Does the lock switch in the toggle bank work properly? BTW, it is a radio receiver, not IR (infrared).

I am doubtful that the BCM had been replaced with a used unit. That's difficult to accomplish without other obvious issues cropping up.

If that were the case, it wouldn't start the car.

 

I'm going with a broken microswitch inside the fob. Happened to me, and a few of my friends. Replacement switches can be found on eBay for a couple bucks... Just need some soldering skills.

 

Got it, thanks.

10-4, I'll try to test it and investigate repairing if its not emitting a signal. I think I recall seeing something at an autoparts place that could determine if a keyfob battery was low/dead.

 

Yea Autozone, Advance, O'Reilly etc. Whatever your close to has the testers along with the battery. Takes alot of guess work out of the equation! Good luck.

 

I just went to O'Reilly Auto and had the keyfob tested. It isn't working. I guess I'll be replacing the microswitch. Thanks for the info Andrew.

Instead of soldering a new microswitch in, can I swap my laser cut key and chip into a used key off ebay? Is that doable?

 

The eBay key is just a blank. It wouldn't come with internals. Even if it did you would still need the dealer to program it, correct me if I'm wrong? I don't believe you can just swap chips?

 

Yes, although I don't know whether it's practical to swap blades between fobs (depends on how the blade is physically attached). You can go the other way -- swap the circuit board in your current key.

This thread covers the relevant concepts: https://www.northamericanmotoring.co...for-cheap.html

 

Swapping blades between fobs is a snap, literally. It's a 2 pin design the blade just snaps on. No worries there.

 

You have the older style key which is different from the OP's. In the newer 3-button key, the case is plastic welded (not designed to be opened, and has to be cut open). In the photos in the other thread, the end of the blade looks like it might be encased in plastic and not easily detachable.

I would transfer the original immobilizer chip into the eBay circuit board and put that into the original shell.