P0141 · blink 24 – Rear O2 sensor heater circuit malfunction (EU spec)

System: Engine control (EFI)
Dashboard light: Check engine light (MIL)
Check-engine blink code: 24
Applies to: 1KR-FE: M300 (Sirion export = JDM Boon M300S/M301S(4WD? see gaps) & Passo KGC10/KGC15). JDM-spec ECU not separately documented
Description: Rear O2 sensor heater circuit malfunction (EU spec)
Detection / symptoms: MIL per chart B8-52..55
Possible causes: Open/short in rear O2 heater circuit
What to check: Unit check B8-221: rear O2 heater 13.0 ohm (+2.5/-1.3) @20C
Confidence: high (factory manual, export spec)

From the factory service material. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights