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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
C0421high severityChassis

Pre-Collision Brake Actuator Circuit

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

What this code means

Malfunction in the brake actuator used by the pre-collision system to automatically apply brakes.

Symptoms

  • PCS warning light
  • Automatic braking will not activate
  • Pre-collision system disabled

Common causes

  • Brake actuator solenoid failure
  • ABS modulator fault affecting PCS
  • Wiring to actuator damaged
  • Actuator mechanically stuck

Diagnostic steps

  1. Test brake actuator solenoid resistance
  2. Command actuator with scan tool
  3. Check for ABS codes that disable PCS
  4. Inspect actuator wiring
  5. Test brake pressure response to PCS command

Repair notes

Replace brake actuator or repair ABS modulator. PCS brake actuation may use the ABS hydraulic unit.

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