CAL Transponder and Immobilizer Systems 2 — Questions and Answers
Question 1: What does the term 'cloning' mean in the context of automotive transponder keys?
- Duplicating the transponder's stored data onto a blank chip (Correct answer)
- Physically cutting a key to match an existing key
- Resetting the immobilizer ECU to factory defaults
- Programming a new key through OBD-II diagnostics
Correct answer: Duplicating the transponder's stored data onto a blank chip
Cloning copies the transponder's crypto ID or fixed code from an original chip to a compatible blank chip, allowing the new key to start the vehicle.
Question 2: Which transponder type is commonly referred to as a 'glass chip' due to its packaging?
- Texas Crypto 128-bit
- Philips Crypto 2
- Fixed-code EM4100
- Texas Instruments TI DST (Correct answer)
Correct answer: Texas Instruments TI DST
Texas Instruments DST (Digital Signature Transponder) chips are often encased in glass cylinders and are widely found in Ford and other vehicles.
Question 3: What is the primary purpose of the antenna ring surrounding the ignition cylinder?
- To power the ECU during startup
- To amplify the RF signal to the BCM
- To energize and communicate with the transponder chip (Correct answer)
- To detect key insertion mechanically
Correct answer: To energize and communicate with the transponder chip
The antenna ring creates an electromagnetic field that inductively powers and reads the transponder chip inside the key.
Question 4: A customer's vehicle starts with the original key but not the newly programmed key. The most likely cause is:
- The new key blade is cut incorrectly
- The transponder data was not successfully written to the new key (Correct answer)
- The immobilizer fuse has blown
- The ignition cylinder needs replacement
Correct answer: The transponder data was not successfully written to the new key
If the blade cut is correct but the car won't start, the transponder chip was likely not properly programmed or cloned.
Question 5: Which of the following best describes a 'rolling code' transponder system?
- A system that uses a fixed ID that never changes
- A system where the crypto value changes with each use (Correct answer)
- A system that stores all valid codes in the ECU permanently
- A system requiring manual relearn after each start
Correct answer: A system where the crypto value changes with each use
Rolling code (or hopping code) systems generate a new cryptographic challenge-response pair each ignition cycle, making replay attacks ineffective.
Question 6: When using an EEPROM programmer to read immobilizer data, which component is most often targeted?
- The key fob battery
- The immobilizer control module or ECU EEPROM chip (Correct answer)
- The ignition coil module
- The body control module relay
Correct answer: The immobilizer control module or ECU EEPROM chip
EEPROM programmers are connected directly to the immobilizer module or ECU chip to extract stored transponder codes for key programming.
Question 7: A Philips PCF7936 (ID46) transponder operates in which frequency range?
- 315 MHz
- 433 MHz
- 125 kHz (Correct answer)
- 2.4 GHz
Correct answer: 125 kHz
The PCF7936 and most automotive transponder chips operate at 125 kHz, the standard low-frequency range for passive RFID ignition transponders.
CAL Transponder and Immobilizer Systems 2
What does the term 'cloning' mean in the context of automotive transponder keys?