Key/EWS experts enter please

[Tbonem3]

El scenario: I have 2 keys; one works fine, but the second, while the buttons all work, will not start the car.

I don't believe anything is wrong with the car - never swapped ecus or any sort of work done to ECU at all besides basic tunes like most of us do.

Question, before buying a new key, is it possible to "reset" the comms between key and EWS? Is the battery (rechargeable as I understand it) the issue? How do you recharge it if the key won't start the car.

Or do I need to hook the car up to INPA or DIS or whatever and do something while the key is in position 2 or some such magic?

Thanks,
Tyler

[e46mpwrd]

When you attempt to start does the engine turn over or nothing at all? Im going to try to find some of the links I used to diagnose a key problem (working tho).
To program keys to EWS you need a AK90. Cant do it via INPA.
You can check the EWS module in INPA, with the key in the 2nd position when you attempt start, it should tell you on one of the menus more info on what is going on with the key.

[heinzboehmer]

Does the car crank? If so that would suggest that it's an issue with your tune. Since you say your other key works fine then I doubt this is the case.

As far as I understand, the EWS antenna in the key is powered by the lock cylinder, so it should communicate with the car even with a dead battery. Re-syncing the key and EWS requires an AK90 programmer (assuming that the issue is that these two somehow got our of sync and not that the hardware in the key is faulty).

[skristedja]

Have you tried reprogramming the key? https://www.bimmerforums.com/forum/s...-reprogramming

I haven't tried this, but I ordered a new key and am planning to try it when I get mine. I highly doubt your key battery is the issue as I have the opposite problem with my key - none of the buttons work (as the battery is likely dead), but the key starts the car perfectly fine.

[heinzboehmer]

Have you tried reprogramming the key? https://www.bimmerforums.com/forum/s...-reprogramming

I haven't tried this, but I ordered a new key and am planning to try it when I get mine. I highly doubt your key battery is the issue as I have the opposite problem with my key - none of the buttons work (as the battery is likely dead), but the key starts the car perfectly fine.

That only works to sync the keys with the GM5. So lock/unlock/etc functions will work, but the key won't start the engine unless it's also synced with the EWS.

[skristedja]

That only works to sync the keys with the GM5. So lock/unlock/etc functions will work, but the key won't start the engine unless it's also synced with the EWS.

Good to know. Guess I'll be ordering an AK90 programmer as well.

[Tbonem3]

Thanks guys.

Yes, to reiterate, my other key works and the car is 100%. It's definitely the key. And it's only the ignition communication - door/trunk locks work.

Car does nothing when attempting to turn over. Everything on dash lights up like normal, but nothing afterwards, not even a click, just nada.

It sounds like I'd need some special equipment or a dealer friend or something to resolve this and $170 on a new key isn't the end of the world.

Any other ideas or helping hands who're capable of reconnecting the comms of key to EWS appreciated, thanks!

It's not something simple like leaving the key in position 2 (maybe put car on the tender) and let it charge back up right?

Do people with 2 keys alternate which they use periodically?

[heinzboehmer]

Good to know. Guess I'll be ordering an AK90 programmer as well.

This is pretty helpful: https://ncs-expert.com/e46-key-programming-ak90-guide

Thanks guys.

Yes, to reiterate, my other key works and the car is 100%. It's definitely the key. And it's only the ignition communication - door/trunk locks work.

Car does nothing when attempting to turn over. Everything on dash lights up like normal, but nothing afterwards, not even a click, just nada.

It sounds like I'd need some special equipment or a dealer friend or something to resolve this and $170 on a new key isn't the end of the world.

Any other ideas or helping hands who're capable of reconnecting the comms of key to EWS appreciated, thanks!

It's not something simple like leaving the key in position 2 (maybe put car on the tender) and let it charge back up right?

Do people with 2 keys alternate which they use periodically?

Nah I never swap out my key. Like I said, the battery doesn't need to be charged to start the car (only needed to lock/unlock remotely), which is the valet key works.

I would start by doing what e46mpwrd suggested. Fire up INPA, go into the EWS module, and look at what the logs say when you try to start the car with the key that doesn't work.

[skristedja]

Any other ideas or helping hands who're capable of reconnecting the comms of key to EWS appreciated, thanks!

I'll be attempting to sync my new ebay key with my car via the ak90 programmer in a couple weeks here. No guarantees that it will be a success, but if all goes well I'll reach out to you and see if I can help!

[exextatic]

Getting a new transponder, programming it with an AK90, installing it into your non-starting key and disabling (locking out) the old transponder in the EWS module should be all that's needed.

When using the AK90, make sure you check the EWS IC's part number before connecting it to the AK90 - certain types of IC need to not have power applied to certain pins (can't remember which off of the top of my head), otherwise it will reset the IC.
In saying that, I've only ran into one that required special handling in an E39, but it is something to be aware of.

[Egone]

Thanks guys.

Yes, to reiterate, my other key works and the car is 100%. It's definitely the key. And it's only the ignition communication - door/trunk locks work.

Car does nothing when attempting to turn over. Everything on dash lights up like normal, but nothing afterwards, not even a click, just nada.

It sounds like I'd need some special equipment or a dealer friend or something to resolve this and $170 on a new key isn't the end of the world.

Any other ideas or helping hands who're capable of reconnecting the comms of key to EWS appreciated, thanks!

It's not something simple like leaving the key in position 2 (maybe put car on the tender) and let it charge back up right?

Do people with 2 keys alternate which they use periodically?

sounds like the transponder for the ews in your 2nd key is no good. You can buy a new key off Ebay (make sure you get the right freq) and an Ak90 off Aliexpress or Ebay and reprogram.

[Pnick]

El How do you recharge it if the key won't start the car.

Thanks,
Tyler

Components
Key with integrated transponder chip
A chip which can both transmit as well as receive (transponder) is integrated in the key. This transponder chip obtains its power from the field built up by the ring coil and uses it to communicate with the EWS control module. This means that no battery is necessary in the key for power supply. Every key or the transponder integrated in it is a unique part. The control module can also differentiate between the individual keys. The key transmits and receives data from/to the EWS control module.
If errors occur during communication between the EWS control module and the individual keys, these errors are stored in the fault memory - separate for each individual key.
Ring coil
The ring coil is mounted on the ignition lock and serves as an antenna for communication between the transponder chip (in the key) and control module.

[NZ_M3]

Use INPA and see if the key that’s not working is transmitting the codes

for the key to communicate it needs to match a fixed code and then the rolling code which then activates the starter signal relay and in term communicates with the dme to say it is ok to fire the fuel pump.

sometimes that rolling codes gets messed up and no longer matches the rolling table saved since last use (happens a lot when you start flashing your dme)

Chances are you just need to make that particular key unused in the ews module and then it will reset the variable code. (You’ll need either an AK90 or PA Soft scanner to do this or an ews editor tool)

I’ll post up some screenshots later about what I am talking about to make it easier to follow.

[NZ_M3]

[Rosie]

Your non-cranking key could also have been disabled in the EWS module (If it had been lost)
You can see and change this with DIS, INPA or PA Soft (Scanner 1.4.0).

If the EWS chip in the key is faulty it is junk - AK90 can only program virgin keys.

Geargrinders write up of EWS is worth a read:-

https://www.bimmerforums.com/forum/showthread.php?2398842-EWS-3-3-101-Why-your-car-won-t-start-and-why-your-mechanic-and-friends-are-wrong