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2023 MAZDA MAZDA3

2.0L I4AWDAUTOMATICgas
Repairs0Labor511Torque3820Fluid9DTC919Battery0Maintenance0Recalls0
P3012moderate severityPowertrain

Camshaft Profile Actuator B Stuck Bank 1

on 2023 Mazda Mazda3 2.0L I4 · AWD

What this code means

The camshaft profile switching actuator for Bank 1, exhaust side, is mechanically stuck. The exhaust cam profile affects scavenging and emissions.

Symptoms

  • Check Engine Light
  • Poor emissions performance
  • Reduced engine braking
  • Slight power loss
  • Failed emissions test

Common causes

  • Oil sludge in actuator passages
  • Faulty solenoid
  • Low oil pressure to actuator
  • Worn actuator mechanism
  • Carbon deposits

Diagnostic steps

  1. Check oil condition and level
  2. Command exhaust cam profile switch
  3. Monitor cam profile position PID
  4. Test oil pressure at actuator
  5. Inspect actuator for carbon buildup

Repair notes

Replace exhaust cam profile actuator. Perform engine oil flush if sludge is present.

Other Powertrain codes on this vehicle

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