P0133 – Oxygen Sensor Slow Response (B1S1)

System: Engine - O2
Dashboard light: Check engine light (MIL)
Check-engine blink code: —
Applies to: Unverified for 1st-gen Passo/Boon; 1KR-FE (toyota-club.net list covers all 1KR-FE variants; 1st-gen KGC10/15 fitment not individually confirmed)
Description: Oxygen Sensor Slow Response (B1S1)
Detection / symptoms: Not given in source
Possible causes: Not given in source (code list only)
What to check: Not given in source; see Toyota/Daihatsu repair manual DTC section
Confidence: low - NOT in Daihatsu M300 factory chart (B8-52..55); likely later-gen/Toyota-built 1KR only

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