Mazda RX-8 2004 Service Highlights page 439

Immobilizer System Release Operation
The ignition switch is turned from the LOCK (ACC) to the
ON (START) position. (Security light illuminates.)
(1) The keyless control module sends data A* to the key
(transponder) via the coil.
(2) The key (transponder) calculates data B from received
data A and sends its specific key ID number and data B to
the keyless control module via the coil.
(3) The keyless control module verifies consistency between the
received key ID number and the previously registered key ID numbers.
(4) The keyless control module makes a calculation using received
data B and compares it with sent data A.
(5) The keyless control module requests data for verification
from the PCM.
(6) The PCM sends data C* to the keyless control module.
(7) The keyless control module calculates data D from received
data C and sends it to the PCM.
(8) The PCM makes a calculation using received data D
and compares it with sent data C.
Engine starting is permitted.
(The security light goes out after approx. 3 s.)
*: Data A and C are different random values each time
KEY
(TRANSPONDER)
End Of Sie
09–14–12
SECURITY AND LOCKS
SATISFACTORY RESULT
SATISFACTORY RESULT
SATISFACTORY RESULT
INSTRUMENT CLUSTER
COIL
KEYLESS CONTROL
MODULE
(3), (4)
(7)
(1)
(2)
UNSATISFACTORY RESULT
UNSATISFACTORY RESULT
UNSATISFACTORY RESULT
Engine starting is not permitted.
(After detecting the error (such as non-verification or
malfunction), the security light illuminates or flashes
continuously for approx. 1 min, and then a DTC is
repeatedly displayed 10 times.)
SECURITY LIGHT
(5), (7)
(6)
PCM
(8)
CHU0914S210