Mazda 2006 MX-5 Service Highlights page 433

SECURITY AND LOCKS [KEYLESS ENTRY SYSTEM]
Immobilizer System Release Operation
The ignition switch is turned from the LOCK (ACC) to the
ON (START) position. (Security light illuminates.)
(1) The instrument cluster 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 instrument cluster via the coil.
(3) The instrument cluster verifies consistency between the
received key ID number and the previously registered key ID numbers.
(4) The instrument cluster makes a calculation using received
data B and compares it with sent data A.
(5) The instrument cluster requests data for verification
from the PCM.
(6) The PCM sends data C* to the instrument cluster.
(7) The instrument cluster 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.
COIL ANTENNA
KEY
(TRANSPONDER)
SATISFACTORY RESULT
SATISFACTORY RESULT
SATISFACTORY RESULT
INSTRUMENT CLUSTER
(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.)
(5), (7)
(6)
PCM
(8)
B3E0914T005
09–14B–7
09–14B