1. Disconnect the negative battery cable.
2. Remove the headlight cleaner switch. (See HEADLIGHT CLEANER SWITCH REMOVAL/INSTALLATION)
3. Inspect for continuity between the headlight cleaner switch terminals using an ohmmeter.


Headlight cleaner switch removal/installationMazda 6 Service Manual: Foreword
Caution
When the engine does not start or stalls and the following DTCs
are not indicated, go to engine symptom troubleshooting.
Note
When the immobilizer system is defective, the engine cannot be
started.
If engine condition is normal but light stays on, inspect for
short circ ...
Mazda 6 Service Manual: Dsc on-board diagnosis
On-Board Diagnostic (OBD) Test Description
(See ABS (ABS/TCS) ON-BOARD DIAGNOSIS)
DTC Table
PID/DATA Monitor Table
Active Command Modes Table
...