1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Trunk end trim.
b. Rear scuff plate (RH).
c. Trunk side trim (RH).
d. Theft-deterrent horn.
3. Apply battery positive voltage to horn terminal A, and connect the horn retaining bolt to ground as shown in the figure, and then verify that the horn sounds.

If the horn does not sound, replace the horn.
Remote Transmitter Battery Voltage Inspection
Theft Deterrent Horn Removal/InstallationFuel Tank Pressure Sensor
Purpose/Function
The fuel tank pressure sensor detects the fuel tank pressure.
Fuel tank pressure sensor is only used for OBD.
Construction
The fuel tank pressure sensor is equipped to the charcoal canister.
A piezoelectric-type sensor has been adopted.
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Forced Ignition On
NOTE:
In order to perform a forced ignition ON, the M-MDS is necessary. If the
servicing is being done outside of an Authorized Mazda dealership, contact an
Authorized Mazda dealership for instructions.
The forced ignition ON procedure forces a power supply to each part when
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Knock Sensor (Ks)
Purpose/Function
Detects abnormal combustion in the cylinder as basic information for mainly
determining the ignition timing.
Detects abnormal combustion in the combustion chamber and inputs it to the
PCM as a knocking signal.
Construction
Installed on the cylinder ...