Key programming
Key programming is carried out after the replacement of a faulty engine control unit or when additional keys are issued to the car owner.
The procedure begins with the engine control unit asking the tester for specific vehicle data. «Clean» the engine control unit records this data, after which you can start programming the key. «Programmed» the engine control unit compares the data received from the test device with the data stored in its memory. If the data matches, programming continues.
If the engine control unit receives incorrect vehicle specific data three times, it rejects the key programming request within 1 hour. The duration of this deviation cannot be reduced by disconnecting the battery or otherwise. After connecting the battery, the timer starts counting from zero.
The key is programmed by turning on the ignition with the key and by additional commands from the test device. The engine control unit writes the relevant data to the EEPROM and transponder memory. After that, the engine control unit performs an identification, which is required to validate the programming process. The programming is then confirmed by a message to the tester.
If the key is already known to the engine control unit based on the programming of the previous key, it is recognized and updated in the EEPROM. The contents of the transponder memory do not change (in a programmed transponder this is not possible).
The engine control unit recognizes an attempt to reprogram a key already programmed during the same programming cycle. It rejects the key request and issues a message to the tester.
The engine control unit also rejects the programming of non-valid keys by displaying a message to the tester. The key may not be valid due to a malfunction of the transponder or for other reasons caused by unsuccessful data entry. The key is considered invalid if the identifications of the transponder and the engine control unit do not match.
A maximum of 4 keys can be programmed.
In the event of an error when using the immobilizer service menu, the state of the engine control unit remains unchanged and a special fault code is stored in the memory.
If, when programming any key, the states of the engine control unit and the key do not match, the test procedure is terminated, and a special fault code is recorded in the memory of the engine control unit.
User password programming
The user password used to start the engine in emergency mode is programmed at the service station. The user selects a four-digit numeric password.
The user password can only be programmed «programmed» engine control unit. Before entering the user password into the engine control unit for the first time, the password status must be «clean». In this case, an emergency start of the engine is not possible.
Programming is done by turning on the ignition with a valid key and issuing a user password from the test device. Upon successful programming, the user password changes from the state «clean» into a state «programmed».
The programmed user password can be changed. This is possible if the user's password is in the state «programmed», and the tester issues permission to access either the old user password or specific vehicle data. After a correct authorization, the engine control unit requests a new user password. The new password remains in the state «programmed» and will be active at the next emergency start of the engine.
If an incorrect user password or erroneous vehicle data is issued to the engine control unit three times, it rejects the request to change the password within an hour. The duration of this deviation cannot be reduced by disconnecting the battery or otherwise. After connecting the battery, the timer starts counting from zero.
User password states
00. Not tested yet.
This state is stored in EEPROM. If erroneous or incorrect data is received from this device, the engine control unit is unable to check this condition and issues message 00.
01. Programmed.
The password in the engine control unit has been programmed successfully.
02. Clean.
This state is entered at the end of the engine control unit production line before the vehicle is released to the end user.
04. Locked with timer.
After a certain number of erroneous entries, the engine control unit is blocked for 1 hour, during which no entries are accepted.
05. Programming not accepted.
This state is set if, for example, the engine control unit is in the neutral state.