Abstract: Memory contents in an electronic key are re-programmed using a base station from a multi-byte pre-existing or default value. If writing the new secret code value is interrupted and results in a partially-written value then a first recovery code is formed comprising a leading portion having values matching a corresponding portion of the pre-existing secret code and a trailing portion having values matching a corresponding portion of the new secret code. The first recovery code is transmitted to the electronic key for comparison with the stored secret code value. The electronic key compares a received secret code value in response to the first recovery code with the stored secret code value. If the comparison detects a non-match, then interaction with the base station is suspended. If the comparison detects a match, then interaction with the base station is continued in order to accept the new secret code value after re-transmission in full from the base station.

Abstract: Memory contents in an electronic key are re-programmed using a base station from a multi-byte pre-existing or default value. If writing the new secret code value is interrupted and results in a partially-written value then a first recovery code is formed comprising a leading portion having values matching a corresponding portion of the pre-existing secret code and a trailing portion having values matching a corresponding portion of the new secret code. The first recovery code is transmitted to the electronic key for comparison with the stored secret code value. The electronic key compares a received secret code value in response to the first recovery code with the stored secret code value. If the comparison detects a non-match, then interaction with the base station is suspended. If the comparison detects a match, then interaction with the base station is continued in order to accept the new secret code value after re-transmission in full from the base station.

Abstract: A write mode for programming selected memory locations of an electronic module with data includes writing data to be programmed into memory into first, second and third data blocks, and a checksum corresponding to data block. A read mode for reading and using data located in memory locations includes reading data from first, second, and third data blocks, determining if the contents of those data blocks is identical to the contents of any other of the data blocks, and using the data from the memory with the contents of any data block whose contents are identical to the contents of another data block.

Abstract: A method and system for relearning a previously programmed, authenticated key. The system includes an electronic control module (ECM) and a key. The method begins when the ECM fails to match an identification code (ID) of the key with all active or disabled IDs that are stored within the ECM. Thereafter, the ECM sends a signal to the key by encryption with a default secret code. If the key does not respond to this signal, then the ECM sends a signal to the key by encryption with one of a series of unique secret codes. The key receives this signal and then transmits an encrypted valid response signal to the ECM. The ECM extracts a key password from the encrypted valid response signal and compares this key password to a module password. Thereafter, the ECM determines that the passwords are identical and the ECM stores the key ID.

Abstract: A method and system for relearning a previously programmed, authenticated key. The system includes an electronic control module (ECM) and a key. The method begins when the ECM fails to match an identification code (ID) of the key with all active or disabled IDs that are stored within the ECM. Thereafter, the ECM sends a signal to the key by encryption with a default secret code. If the key does not respond to this signal, then the ECM sends a signal to the key by encryption with one of a series of unique secret codes. The key receives this signal and then transmits an encrypted valid response signal to the ECM. The ECM extracts a key password from the encrypted valid response signal and compares this key password to a module password. Thereafter, the ECM determines that the passwords are identical and the ECM stores the key ID.