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2019 MAZDA MAZDA3
2.0L I4•AWD•AUTOMATIC•gas
6 active safety recalls on this vehicle — view recalls
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Repairs0Labor551Torque3627Fluid8DTC919Battery1Maintenance0Recalls6
P1345critical severityPowertrain

No CMP or SGC Signal

on 2019 Mazda Mazda3 2.0L I4 · AWD

What this code means

The PCM is not receiving a Camshaft Position sensor or Signal Generator C signal. Without this signal, the PCM cannot determine camshaft position for sequential fuel injection and ignition timing, resulting in a no-start or severe running condition.

Symptoms

  • Engine cranks but will not start
  • Engine runs very rough if it starts
  • Check Engine Light
  • Backfiring

Common causes

  • Faulty CMP sensor
  • Damaged CMP sensor wiring
  • CMP sensor connector disconnected
  • Damaged reluctor ring
  • Timing belt or chain failure affecting cam signal

Diagnostic steps

  1. Check for CMP sensor signal on scan tool during cranking
  2. Inspect CMP sensor connector and wiring
  3. Test CMP sensor resistance
  4. Check CMP sensor air gap
  5. Verify timing belt or chain condition

Repair notes

Replace the CMP sensor if it is not producing a signal; check timing belt or chain condition.

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Other Powertrain codes on this vehicle

🔧 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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