Immobilizer Control Module
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 GMC Yukon XL, 2015 GMC Yukon, 2015 Chevrolet Tahoe, 2015 Chevrolet Suburban, and 2015 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
The Immobilizer Control Module contains an immobilizer coil which surrounds the ignition cylinder (without BTM) or is located near the transmitter pocket/slot (with BTM). The coil passively powers the transponder located in the ignition key. When powered, the key transmits its unique value to the Immobilizer Control Module, which is then relayed to the BCM via a LIN serial data circuit. The Immobilizer Control Module also receives B+ and ground from the BCM.
The Immobilizer Control Module is used to:
- Learn keys
- To start vehicle with or without RF interference
- To start vehicle when key battery is dead