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2004 MAZDA MAZDA3
2.3L I4•FWD•AUTOMATIC•gas
3 active safety recalls on this vehicle — view recalls
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Repairs0Labor551Torque3638Fluid6DTC730Battery1Maintenance0Recalls3
P1309high severityPowertrain

Misfire Detection Monitor

on 2004 Mazda Mazda3 2.3L I4 · FWD

What this code means

The PCM misfire detection monitor has identified a misfire condition but cannot pinpoint the specific cylinder. The CMP sensor synchronizer may not be providing the signal needed for cylinder-specific misfire identification.

Symptoms

  • Check Engine Light
  • Engine misfires
  • Rough running
  • Reduced power
  • Failed emissions test

Common causes

  • Faulty CMP sensor or synchronizer
  • Worn spark plugs or ignition coils
  • Fuel injector malfunction
  • Low compression in one or more cylinders
  • Vacuum leak at specific cylinder

Diagnostic steps

  1. Check for companion cylinder-specific misfire codes
  2. Inspect CMP sensor and synchronizer alignment
  3. Test spark plugs and ignition coils
  4. Perform fuel injector balance test
  5. Run compression test

Repair notes

Verify CMP synchronizer alignment and diagnose the root cause of the misfire.

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🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
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