[fadyeid]

I need to ask could I use transponder chips like ( PCF 7935 , 7936 )

again or just need to buy new one ?!

[BMWS1000RR]

Depends on the type of programmer device you have. Most lock the chip upon programming.

All original Philips/NXP PCF7936 are shipped from factory with the same factory default password (called the ISK or Initial Secret Key) that, with the right equipment can be used to talk to it. Aside from the different features, all the PCF79xx range work like this.

When you take that "Virgin" transponder and pair it up to the vehicle, during the process the default ISK is changed to a different one, locking the transponder to that cars immobilizer setup.

At this point, most people think that the transponder is now permanently locked and leads them to think that its OTP. The truth is that if you had the access to the new ISK (stored in the cars immo) you could talk to it just as easily as before. You could also reset it back to its factory settings and make it reuseable.

Products such as transponder programmers that advertise the fact that they can unlock certain transponders must be relying on that the fact that in some car manufacturers immo setups they either dont change the ISK from default or change it to a fixed value across certain vehicle models.

As far as i am aware, TPX3 or TK60 keyheads which are a functional clone of the PCF7936 has the ability to be rewritten a limited number of times. It would make sense from a business point of view that they would impose these limits so they sell more. I think some of the cheaper chinese clones don't have a limit.

[fadyeid]

Thank u so much for this reply I really learned a lot from it

now I have got a big deal about 1000 ecu + bsi and needed to be matched together with transponder chips so I have got aout 100 chip could zed bull reset this chips !? or no way

[zmann]

Look like you're focusing on PSA cars (with PCF7936 Hitag II family), the new password is not store in the BSI nor any other module. Therefore you have very much less opportunity or null to find the new correct password to unlock the chip even PIN code is known. But the known-PIN-code used chip can be reused if you agree to use this PIN code to be programmed to new car.

On some older PSA cars with PCF7931/7935 chip you can reuse them straight away.

[fadyeid]

Look like you're focusing on PSA cars (with PCF7936 Hitag II family), the new password is not store in the BSI nor any other module. Therefore you have very much less opportunity or null to find the new correct password to unlock the chip even PIN code is known. But the known-PIN-code used chip can be reused if you agree to use this PIN code to be programmed to new car.

On some older PSA cars with PCF7931/7935 chip you can reuse them straight away.

yes I am a beginner only 6 months in this job but I am an electronics engineer , so I just work with all Peugeot cars this days , so your answer I cant reused the 7936 but 7935 could be used again by what ? gambit or which tool

[zmann]

7935
use PSA diag tool to program the used chip to the same model or similar cars
clone used chip (precoded as ID45 and not ID33) with tool like Zedbull or Zedbull+EFfI, somehow my EFfI version not working on this.