Transponder and Immobilizer Systems Flashcards
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Read the first 7 Transponder and Immobilizer Systems flashcards as text
What does 'IMMO OFF' refer to in automotive locksmith practice?
Answer: Bypassing or disabling the immobilizer system via ECU modification
IMMO OFF is a technique where the ECU firmware is modified so the vehicle no longer checks for a valid transponder signal, effectively disabling the immobilizer.
Which tool function is specifically needed to program a Megamos Crypto (ID48) transponder?
Answer: Crypto calculation using the chip's challenge-response data
ID48 transponders require specialized crypto calculation tools that can perform the mutual authentication algorithm used by Megamos Crypto chips.
What is the function of a 'key learning' or 'key registration' procedure performed via OBD-II?
Answer: To add a new transponder's ID to the vehicle's authorized list
OBD-II key learning writes the new transponder's unique ID into the immobilizer control module's approved key list.
A technician finds that a vehicle requires a 4-digit PIN code before adding new keys via OBD. Where is this PIN typically sourced?
Answer: From the vehicle's VIN-based database or EEPROM extraction
PIN codes for key programming are typically retrieved from a VIN-linked database service or by reading the immobilizer EEPROM directly.
Which Honda transponder system uses a 13.56 MHz frequency and is considered a high-security chip?
Answer: Honda G-chip (46E)
Honda's G-chip uses 13.56 MHz high-frequency communication and incorporates crypto authentication, making it more secure than low-frequency 125 kHz chips.
What happens during the 'challenge-response' phase of a crypto transponder authentication?
Answer: The ECU sends a random number, and the transponder returns an encrypted answer
In challenge-response authentication, the ECU generates a random challenge; the transponder uses a shared secret key to compute and return the correct encrypted response.
A locksmith is asked to add a key to a Toyota with a 4D transponder. Which method is most commonly used when no working key is available?
Answer: Dump the immobilizer ECU EEPROM and use a specialized programmer
Without a working key, the most reliable method is to read the immobilizer ECU's EEPROM dump and use a transponder tool to generate or write the correct 4D crypto data.