P0130 · blink 21 – Front oxygen sensor circuit
- System
- Engine - O2
- Dashboard light
- Check engine light (MIL)
- Check-engine blink code
- 21
- Applies to
- 1SZ-FE (by platform)
- Description
- Front oxygen sensor circuit
- Possible causes
- Trouble area: 1.Open or short in front oxygen sensor circuit 2.Front oxygen sensor 3.Air leak or fuel pressure fault
- What to check
- Checking points: 1.Check sensor connector and wiring 2.Check for vacuum or exhaust leaks 3.Replace sensor if signal does not switch
- 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