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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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Repairs0Labor987Torque6478Fluid16DTC2264Battery2Maintenance0Recalls2
B0104high severityBody

Immobilizer Control Module Communication

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

What this code means

The immobilizer control module is not communicating with the ECM/PCM. Both modules must agree before engine starting is allowed.

Symptoms

  • Engine will not start
  • Security light on
  • No communication with immobilizer module
  • Multiple no-start codes

Common causes

  • Immobilizer module failure
  • CAN bus wiring issue between modules
  • ECM/PCM fault
  • Power or ground issue to immobilizer module

Diagnostic steps

  1. Check CAN bus communication
  2. Test immobilizer module power and ground
  3. Scan both immobilizer and ECM for codes
  4. Check wiring between modules
  5. Try key relearn procedure

Repair notes

Repair CAN bus wiring or replace immobilizer control module. Modules may need to be paired.

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