key fob not locking but locking

[jamiecarpenter]

My key has stopped locking the car but still unlocks the car and the boot without issue (using the fob rather than putting the key in the locks). Anyone else had this issue. Everything else seems to be fine with the car. Im hoping its not down to the GM5 module.

 

[axelleveau]

Most likely it is the switch in the key body under the lock button which is playing up. That explains why all other functions work. I had this issue on a key when I bought my car and ended up replacing said switch while I was replacing the battery. It is precision soldering work so if you are not experience you should find a key place that does that work or an electronics shop

 

[fredej]

Probably due to low voltage reported from the key battery.

This is what BMW technical documentation says;

Voltage monitoring

The charge level of the standard/rechargeable battery in the key fob transmitter when a button is pressed is monitored.

If the voltage drops to a lower limit, the key fob transmitter signals the battery condition to the basic module. The basic module processes that information as follows:

- The command "Lock vehicle" is not executed. All other functions are allowed.
- The low voltage is registered on the basic module

The message is analysed by the diagnostic program for the radio remote control. It is automatically deleted once the voltage level on the key fob transmitter has been OK again 5 times in succession.

If low voltage occurs, the following operations are required:

- On key fob transmitters with standard battery, the battery must be replaced
- On key fob transmitters with rechargeable battery, the battery must be charged for at least 30 minutes in the ignition lock.
A non voltage-dependent memory in the key fob transmitter ensures that the initialisation data is not lost even if the battery is completely discharged.

 

[jamiecarpenter]

Thanks for the information ill try recharging it and then may need to replace the keys battery if this does not work.

 

[Meds]

I had the same.
1 key worked both lock and unlock but the other key just unlock.
I tried charging using an electric toothbrush charger but still no better.
I cut the key open and replaced the battery, then paired the key to the car.
All sorted..

 

[colb]

If one button works then seems likely the other button switch has failed refurbish kits are on ebay or you could send the key off to have it repaired if you don't fancy soldering a new button switch yourself.
The transponder in the original key is part of the pcb so it can't be just put into a replacement key like the Chinese keys, they come with a separate transponder in them that requires coding.
https://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=bmw+z4+e85+key&_sacat=0
Refurbish service here https://www.ebay.co.uk/itm/404467744662?itmprp=cksum%3A4044677446626d98ef896a62464b998b783a2795db11%7Cenc%3AAQAJAAABoOJbA%252BMwXOh1UagdHfPsbHl907Q5K%252Fuy7pvfBZPF09uUwnBUFjH7Kpe3NhGcfGVocw41EV%252FMfD1qDBHIoUFJTjwsQCAxgHNkIn4ccVLqZHvFdqgcF3TLq%252F6Nys6s5NGtcW2BGzEcEknrMnM3kiPjcRRXttPXdIBEVBgFu658oIWP6a3fqggZFs8LMhy6ReTAyfdv%252BzWAqhdbZr%252Bj1WO1ofNpDMY4ql72HDLJxjhEj6uUZgrlQ6OfU72f0PtczOiB9ymtN4SiRpNRhaIFrKXO6gTjVHwnvB4fns0vXX4ZUZfX8R6Eg8P5he%252FCJnyaz%252BcCulFwyT4AkAEkILugj4PC9BZY4t298TQOq6KEjNYcZjnnCAIknhNxboYGp64z9q2wDJNqC54A9CIN%252FXe1L%252BtTCo%252BYQZL9gc%252F%252Bnck5g9mTk5jeUhKVnkIiKQmbuIzL7Y5cxc0vw9NLR9S4jN8veqslDEAt4%252FgXYz5rxJt%252B8ZyB1jb%252BIWidriTe354YlxBhwLN50edO9slWRwj4DccppSBcxk2OcX0kmlXrG3E3cnWcmbj9%7Campid%3APL_CLK%7Cclp%3A4429486&itmmeta=01J2ZXS8XS88FH3AK94YEGK7XE
If you go for a complete replacement key then you have to have the blade cut and the transponder coded to your car, mobile locksmiths can do this but they do like to supply the blank key as well so finding someone to cut it can be problematic. Locksmith will code it to the car and this involves taking the EWS module out so they can read it with their kit. They will charge you circa £130 to supply cut and code.
Alternative is to go to BMW and see what they will charge for a new key.
Once you have repaired or new key it has to be synced to the car with all other keys you have by doing a finger dance using the fob buttons, instructions in threads on here.

 

[jamiecarpenter]

Thanks for info I think i may go for the ebay service option.

 

[Meds]

I'd suggest trying a new battery then pair the key using the process well documented on the interweb (and on this forum, too) .
It fixed my symptoms, which were the same as yours.

 

[Fred Smith]

A bit of a story. 10 years ago a key on my mitsubishi stopped working, so I took it apart to change the battery and it didn't want to go back together. I ended up leaving it, no probs, fast forward ten years (most of which with a key that doesn't work remote) and this other key falls apart and stops working and I am screwed - can't get the car to start let alone drive.

After a lot of effort (including one person who said he'd come out then stopped communicating with me, and another who wanted £475 to come out and supply one new key, £150 more for the second) I found a local auto locksmith who seemed decent.

I ended up going there (no call out fee), and over the course of a couple of weeks they -

Refurbished two Mitsubishi keys (new blades and case)
Got the remote locking working on two keys for the Z4 (one BMW key, the other key is - apparently - an audi-style replacement) (in theory I could have done this myself, but when I tried I failed. Pretty sure I would have got there in the end, but when you're parked outside a locksmith anyway...)
New battery on a key for the other half's Fiesta - supplied and fitted

Total - £95 (would have been more if I hadn't got really lucky and found a missing transponder in with the degraded rubber in the drivers footwell)

Morals of the story.

Don't try to get by on one key for a car - it will stop working at some point and then you will be screwed.

Find a decent auto locksmith local to you and use them - in the scheme of things the cost can be pretty reasonable and having keys that work fully is nice! Anyone local to Guildford who wants a recommendation - Fidelis Security and Locksmiths

Edit - the morals of the story are ones that might be pretty obvious to most people, and I am not saying don't try to DIY especially things that are (in theory at least) simple like the procedure to get the remote working... but keys can be a pain and a decent pro can be very reasonable.

 

[colb]

Good advice from Fred as a result of his experience with keys. My Z4 only came with one key and that was a little beat up. I sent for an ebay replacement and had the blade cut at an old fashioned independent cobblers and key cutting guy up in the valleys of South Wales, mainstream cutters like those outside the Supermarkets didn't want to know when asked. Once the blade was cu.t I then had to get the transponder coded to the car in order for it to start the car. I did try using an AK90+ key coding tool but failed to get it to read the ews module consistently so I could code the key. Gave up and found a mobile locksmith who came and used a far more advanced 3k key coding machine, he had to solder wires directly onto the ews processor and read the key details then code the new key, using one of the 10 key slots that had been used before but that I didn't have the key for. Ews put back in the car and key tested, started the car fine. Resynced all keys to the car using the button pressing sequence one after the other and all synced ok. The coding did cost me £130 for my own key to be coded, the blade cut cost me £9.
Just been through a problem with my Z3 key, the pcb failed altogether inside the key, bought a new key off ebay and simply put the new pcb into the old key and synced all my keys back to the car. All good I am glad to say.