Have Citroen C4 2015 to read pin code, I use OBDSTAR key master DP to do the work perfectly. I share the procedure in the following paragraph.
Insert the key into the ignition.
Connect OBDSTAR Key Master DP to the Citroen C4 2015, tap “Diag Program”.
Tap “Citroen/ Peugeot”.
Turn the ignition on and off, then press “Enter” and then turn on the ignition switch.
Reading security code.
Read out the security code: AHPD.
OBDSTAR Key Master DP is really a nice tool to read out the pin code quickly.