Prelude Type-SH L4-2156cc 2.2L DOHC (VTEC) MFI (1997)
Technical Service Bulletin # 96-051
Antitheft - Information on the Immobilizer System
NOV 4, 1996
Information on the Immobilizer System
The 1997 Prelude is equipped with a theft deterrent feature called the immobilizer system. When the correct key is used in the ignition switch, a
transponder inside the key sends an identification (ID) code to the immobilizer receiver. The receiver then sends the code to the immobilizer control unit,
allowing the engine to start. If an incorrect key is used in the ignition switch, the engine's fuel delivery and starter circuits are disabled.
This bulletin gives you information on system components, adding or replacing keys, replacing components, and emergency starting procedures.
Additional information on the immobilizer system is in section 23 of the 1997 Prelude Service Manual and in the PROformance 1997 Prelude
Technician's Information Guide.
WARRANTY CLAIM INFORMATION
None. This Service Bulletin is for information only.
Immobilizer System Components
The immobilizer system has five main components:
Engine control module (ECM)
Immobilizer control unit
Immobilizer indicator light
keys: 2 master keys (black grip), 1 valet key (gray grip), and 1 learning key (red grip)
Engine Control Module (ECM)
The ECM is on the floor of the passenger compartment. When it receives the correct signal from the immobilizer control unit, the ECM enables the fuel
Immobilizer Control Unit
The immobilizer control unit is below the dashboard, on the left side of the steeling column. When the ignition switch is turned on, the control unit sends
power to the transponder through the immobilizer receiver. When the control unit receives the ID code from the transponder, it compares it with the one
in its memory.