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2021 TOYOTA C-HR
2.0L I4•FWD•CVT•gas•M20A-FKS
1 active safety recall on this vehicle — view recalls
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Repairs0Labor476Torque3059Fluid7DTC1942Battery1Maintenance0Recalls1
P0438moderate severityPowertrain

Heated Catalyst Temperature Below Threshold (Bank 1)

on 2021 Toyota C-HR 2.0L I4 · FWD

What this code means

The bank 1 heated catalyst is running below its expected operating temperature. The ECM detects the catalyst is not warming up correctly.

Symptoms

  • Check engine light on
  • Failed emissions test
  • Elevated tailpipe emissions

Common causes

  • Faulty heater element
  • Heater circuit wiring fault
  • Failed relay or fuse
  • Degraded catalytic converter

Diagnostic steps

  1. Verify heater circuit power and ground
  2. Inspect wiring and connectors
  3. Test heater element resistance
  4. Replace heated catalyst or repair wiring
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