- How the Circuit Works
The immobilizer system is designed to prevent the
car f rom being started without the owner's ignition
key. lf an attempt is made to start the car without
the correct key, the immobilizer system will disable
the car's fuel supply.
The immobilizer system consists of the ignition key,
immobilizer receiver unit, immobilizer indicator
light, PGM-FI main relay, fuel pump, and the PCM
or ECM.
With the ignition switch in ON (ll) or START (lll), the
immobilizer receiver unit and the PCM or ECM
receive an "ignition on" signal through fuse 44 and
the PGM-FI main relay. The PCM or ECM then
sends power to the ignition key transponder through
the immobilizer receiver unit. The transponder then
sends a coded signal back to the PCM or ECM
through the receiver unit. lf the signal is correct, the
PCM or ECM will energize the car's fuel supply
system by grounding the PGM-FI main relay. The
immobilizer indicator light flashes a code to indicate
that the correct key has been inserted. lf the
ignition key signal is not correct, the PCM or ECM
will not energize the car's fuel supply system by not
grounding the PGM-Fl main relay. The immobilizer
indicator light then flashes a code to indicate that an
incorrect key has been inserted.
Refer to the Service Manual (Section 23,
Body Electrical) for specific tests and
troubleshooting procedures.
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