Key does not lock/unlock (both remote and physical key)

I just bought a used 2003 325i and was told that the battery in the key was dead so the remote doesn't work and there is only one key. Okay, no problem I thought.

Now that the car is mine, I come to find out that the physical key itself does not at least lock the driver's door either when inserted and turned either way.

Okay, the seller got away with this sale without full disclosure and I'm eating the cost on getting this fixed.

My Googling discovered that for the remote part, the embedded rechargeable battery eventually fails requiring a brand new expensive master key from the dealer (alternatively, there are DIY instrux available to replace the battery).

But are there any general ideas on why the key physically can not lock the door via the cylinder? I can't believe it would also have something to do with the dead battery, so there must be another defective component(s) somewhere. I came across a site mentioning that this issue could be due to a faulty GM5 module (which also controls the interior lights, wipers, alarm-none of which I'm aware of having any issues with). This is getting me worried at the potential costs and the seller's words of "there's absolutely nothing wrong with the car but my wife loves her new Camry") comes back to haunt me...

I've had a 1993 318is long ago (my one and only BMW) and never experienced anything like these key problems.

Help!

this might be a stretch but i still think that the key needs to have some power in order to unlock the car via the doors, because when i turn my key in the doors it still sounds the same (like if i just pushed the unlock button), which leads me to believe that I am not physically unlocking the door, but the car is doing what it normally does, the key is just in the door.. i could be totally wrong though, just a thought

i guess all you can do is replace the battery, youve got nothing to lose

Yea, I was going to replace the battery, but also buy a new master key in order to have at least two keys on hand in case I ever lose one (happened to my girlfriend once). I truly hope that's what it is, but does the special "Spare Master Key" that can fit in your wallet also contain a battery? The FOB head looks awfully tiny to house a battery, at least as depicted in my owner's manual...

Upon further reading of my "new" owner's manual, utilizing the key in the physical door lock cylinder offers many different options: turning once unlocks driver's door; twice unlocks all doors; open the power windows and sunroof by holding the key in the unlock position; close the power windows and sunroof by holding the key in the lock position.

Thus, it seems to confirm your suspicion that the door lock cylinder is not physically attached to the door locking mechanism and is just another electrical device that sends signals to the Central Locking System. Meaning, if the battery in a Master Key is dead, it will no longer respond as a security precaution.

Only time I can think that my key didn't work in the door was when I put the key inside a car door that wasn't mine. I've put my 328ci key inside a 645 and it wouldn't turn duh. lol

I've had the key battery die on me and I was still able to unlock the car. Also was able to unlock the door when the car battery was disconnected. Your key doesn't have to have power to open the door manually.

Maybe the previous owner put in the wrong cylinder in? I would have someone check it before you spend any money.

Originally Posted by mofunk

Maybe the previous owner put in the wrong cylinder in? I would have someone check it before you spend any money.

The door cylinder turns with the key but neither locks nor unlocks the door.

I talked to a repair shop owner this morning and he tells me that the key nor battery has anything to do with the door cylinder failing to lock/unlock; the problem could be with the cylinder and/or the lock actuator ($300 in parts), the Central Locking System or General Module. He also could order a new cut and programmed key, but needs my registration (I still only have the pink slip as the DMV is closed) and driver's license; hopefully, this will be cheaper than thru the dealer.

He will look at it no charge Monday morning and at least test if the remote portion of the key just needs to be reinitialized, so I'll keep y'all posted...

Cool keep us posted. I knew it didn't have to do with the battery. Like I said I've opened my car plenty of times with a dead key battery and the car battery unplugged.

The shop finally got the part and replaced the cylinder and voila! Door locks/unlocks with keys!

Whew.

Now to get a new key ordered so I get a working remote. I will also DIY battery replacement on the original key so as to have two working keys on hand.

You might just want someone like a dealer diagnose your remote. On our touring, it took two new remote sensor modules and a new rear corner window (has the key sensor antenna in it) to get it working again. It "ain't" always the battery in the key. We also needed the cylinder in the door for manual unlocking. Total: $2,000.

Wow. Well, I'm just hoping that because the car (and ergo, the key battery) is over 10 years old, that it has to be the battery. A buck-fifty for a new key isn't really a waste as I want two keys anyway, so if it ends up being more problematic, then I will address it then.

Thanks for the heads-up tho!

I had the same issue, key wouldn't lock/unlock then the cylinder to manually lock and unlock goes out. I ordered a new battery but that didn't work. The end result
was paying BMW $200 for a new key, just happy I am able to lock/unlock my doors now and be at peace.

Just something to ponder, but was the car ever in an accident? Maybe the door replaced? Maybe a half way job was done replacing the door but not the key cylinder? Sounds like the key belongs to another door? Or the door belongs to another Key!
Hoodlum.

I checked my door thoroughly, and if it was off another car, I couldn't tell. The hinge nuts do not look like they were disturbed at all: the original paint appears to be intact and there is no evidence of repainting or overspray anywhere around the door, hinges and body door opening.

Regardless, the new key works like a charm and I'm glad to have remote lock/unlock capabilities once again (my, have I gotten spoiled since my first car: a 1966 Mustang GT fastback, A-code with manual everything).