US 5,684,454 AGranted

Anti-vehicle-thief apparatus

AssigneeMazda Motor Corporation

InventorsFutoshi Nishioka, Tetsushi Hosokai, Atsushi Okamitsu, Yoshimasa Kitaki

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Abstract

An anti-vehicle-thief apparatus having an immobilizer unit for comparing a specific first code received from a transponder to a stored code just after an engine is started, and when these codes are identical, outputting a second code to an EGI unit, the EGI unit for comparing the second code to a stored code, and when these codes are identical, permitting the engine to continue operation, a CPU for counting the number of times that an ignition switch power supply is turned ON and OFF during a code comparison time period, and backup RAM capable of storing the counted number of times that the ignition switch power supply is turned ON and OFF for a predetermined time period. When the ignition switch power supply is turned ON and OFF repeatedly more than a predetermined number of times, the EGI unit causes the engine to stop.

Claims20

Dependent claims

An anti-vehicle-thief apparatus comprising:

code comparison means for comparing a first code received from a sending unit with a code stored in a receiving unit after an engine is started and, when the first code and the code stored in the receiving unit are identical, outputting a second code to an engine control means;
said engine control means for comparing the second code to a code stored in said engine control means and, when the second code and the code stored in said engine control means are identical, permitting the engine to continue to operate;
code comparison operation verification means, provided in said engine control means, for verifying whether or not it is possible to perform the code comparison by said engine control means after the engine is started;
and
engine stopping means for causing the engine to stop when a code comparison by the code comparison means or the engine control means determines that the codes are not identical, or a verification by the code comparison operation verification means verifies that it is not possible to perform code comparison.

2 more elements

Dependencies are inferred from the claim text.