P0141 – Rear oxygen sensor heater circuit

System: Engine - O2
Dashboard light: Check engine light (MIL)
Check-engine blink code: —
Applies to: 1SZ-FE (by platform)
Description: Rear oxygen sensor heater circuit
Possible causes: Trouble area: 1.Open or short in rear oxygen sensor heater circuit 2.Rear oxygen sensor heater
What to check: Checking points: 1.Check heater fuse and wiring 2.Check heater resistance
Confidence: medium (Toyota Echo 1999–2002 factory diagnostics, same XP10 platform; not confirmed on JDM 1SZ-FE)

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