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2020 MAZDA MAZDA3
2.5L Skyactiv-G I4 (186 hp)•AWD•AUTOMATIC•gas
2 active safety recalls on this vehicle — view recalls
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Repairs0Labor984Torque6456Fluid16DTC3770Battery2Maintenance0Recalls2
P1605moderate severityPowertrain

PCM Keep Alive Memory Test Error

on 2020 Mazda Mazda3 2.5L Skyactiv-G I4 (186 hp) · AWD

What this code means

The PCM Keep Alive Memory self-test has detected an error. The PCM cannot properly store or retrieve adaptive learning values from its internal memory.

Symptoms

  • Check Engine Light
  • PCM defaults to base calibration
  • Rough idle initially after restart
  • Harsh transmission shifts

Common causes

  • KAM circuit voltage intermittent
  • Faulty KAM fuse or relay
  • PCM internal memory failure
  • Battery cable providing unstable voltage

Diagnostic steps

  1. Check KAM fuse and relay
  2. Test KAM circuit voltage at PCM connector
  3. Check battery and alternator output
  4. Clear code and retest; if recurring, suspect PCM failure

Repair notes

Check the KAM circuit power supply; replace the PCM if internal memory has failed.

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