Table of Contents
Advertisement
ICU condition and status
The ICU has two possible conditions: "Locked" or "Unlocked".
In addition, three possible statuses :"Virgin", "Learnt" and "Neutralized".
Locked condition
The ICU will stay in the locked condition as long as no valid transponder code has been received. The ICU sill
automatically go to lock condition a regular time after key OFF. As long as the ICU is in the locked condition, engine start
is impossible, since the ICU answers any ECM request with dummy data. Exceptions to this rule are made if either the
ECM or the ICU is in virgin state.
Unlocked condition
Only if the ICU is in the unlocked condition, engine start is allowed.
Virgin status
This status represents the delivery condition of the ICU. The MIN has been programmed at the factory in EEPROM. The
VIN has not been programmed yet; it will be origrammed at the car manufacturer's end-of -line test. In this status, if the
ECM is also in virgin state and the MIN of the ICU are the same, engine start is allowed.
Learnt status
This represents the normal operation of the ICU, where the VIN has been learned. When the ECM sends a request
containingthe same MIN, then if the ICU is unlocked, the response to the ECM will contain a code based on the VIN. If
the ICU is locked, the response will contain dummy data.
Neutralized status
To replace a part of the system(ICU, ECM), the ICU and the ECM have to be set to neutralized state by a <<read
passcode >> request from the diagnostic tool. In this status, engine start is never possible
Following flow diagtam shows the possible transitions between statyuses:
Advertisement
Chapters
Table of Contents
