
Diagnostic Procedure

Dtc 18
Dtc 21Mazda 6 Service Manual: Noise filter inspection
Brake Light Noise Filter
1. Inspect for resistance and continuity between the noise filter terminals
using an ohmmeter.
If not as specified, replace the noise filter.
Rear Window Defroster Noise Filter
Inspect for resistance and continuity between the noise filter terminals
using an ...
Mazda 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 ...