Key coding & EWS
 

Just as a matter of interest Ive been playing around with my EWS Editor Lite program to see what it can and cant do while waiting for some new key chips to arrive and as I had a spare EWS module, thought id see if you can code existing old keys from other Rover 75 cars to the EWS.
Info says it can be done..
I had a coupple of old Rover 75 keys so tried it out and found a couple of interesting things,the program definately reads the old keys and it will code the old key to the EWS -EXCEPT it seems to always want to take key position 00 and will replace the key that is already listed on the EWS at 00.
Unfortunately key 00 is usually the active one but this is fine if you have no key or your one key you have is listed at 01 or 02 but in my case,the one working key was listed at 00 so it would have been pointless to do it.
Pain in the a...se as no matter what even if I tagged the key as 03 or whatever number,the key data would then change to the data that already existed for the key listed in the EWS at position 03.
Suppose its fine for a car with no keys but seems you need blank chips to take up the spare key data (KEYS 3 TO 9 )from the EWS.
At least you can use the circuit board in the old keys.

additional info - seems the original transponder chips ,PCF7930 are not a re writeable chip ,once coded thats it. ,the current chip to use appears to be a PCF7935.

Pity, would have been very helpful down under.

Sure would although it appears a couple of auto locksmiths around here now have similar software and claim they can code Rover 75 keys to the EWS.
As you still need to get the locksmiths to cut the blade for the key might be able to strike a deal to get the key cut and programed,especially if you know how easy it is to do it.
My thought is the chips are about $8 a pop,bought the program for about $100, second hand keys were free. Only cost should be for the blades to be cut.
Had one guy quote $50 just to cut one blade.

If you attempt to copy a key transponder to the EWS, yes it can be done.......however the EWS will see this as a data mismatch as the VIN is locked in the transponder thus making the transponder useless.

The PCF7930AS has the security fuse blown after programming, meaning it cannot be overwritten with new data from another EWS, again meaning used transponders cannot be reused.

Brian :D

brian, your a wealth of wisdon regarding this stuff.
I did wonder if the factory fitted PCF7930 chip could be re coded but obviously not.
I bought some of those chips (PCF7935) you put me onto and just waiting for those to arrive.
As you describe,I could get a used key to list in the EWS but as you say when you go to verify the EWS, kept coming up as a mismatch no matter what I did which explains exactly what you say.
I notice on the EWS there are a number of keys( 2 or 3) listed as active and you can see those keys full details (variable and fixable ?) codes.
All the other keys listed seem to only have the first part of the code and then a bunch of 'F"s in the coded area.
If i code a new chip to one of those keys with only part of the code revealed will it work ? I think I read somewhere that when you use it the cars body control unit fills in the code for that key ?

The first part is the fixed code of the key, the second variable part changes every time the key is turned ;)

If you uncheck the box "used key" you will find the variable part of the code disappears and is replaced with FFF's

Ok , got the blank chips ,plugged in the EWS Editor Lite,read the EWS module out of the car, coded a blank transponder chip using one of the spare keys listed in the EWS and low and behold I now have a spare key that starts my car, only issue is the remote controls do not function with that key.
Still work fine with the original.
From what I gather the EWS talks to the ECU and if all is correct it will allow the car to start BUT the body control unit is the thing that govern locking etc so if it doesnt recognize the new key it wont allow any remote locking to happen.
Ive tried the press the fob lock button 4 times etc,stand on your head and scratch your ...... but nothing appears to want to synchronize the new fobs remote.
Wonder if the transponder chip needed to be in the fob when coding it to the EWS,as in does the fob itself have some impact on the programing ?
Need one of you gurus out there!!!!!

The transponder and remote fob are 2 separate systems, you have to program the remote fob into the bcu before it gets recognised.

The answer is quite simple I'm afraid :(

The immobilisation and remote central locking are two entirely separate systems.

Locking is controlled by the BCU, and immobilisation by the EWS.

In programming a new transponder, yes the car will start using that key, but for the locking side of things to work, the remote board must be introduced to the car using T4.

Still, it's still a lot better than having simply a "dumb" key ;)

Brian :D

Hmm, I must be needing another cup of coffee, running a little slow this morning :getmecoat: