Lambda sensor upstream catalyst
â–¶ How to fix
- Check primary oxygen sensor LSU lines before catalyst - Check primary oxygen sensor LSU plug connection before catalyst and EGC4 - Renew primary oxygen sensor LSU before catalyst
What you'll see
No driver-visible symptom recorded.
System reaction
- Lambda regulation is locked - Vehicle has higher emissions - Engine runs disturbed - Vehicle might sutter on dynamic drive
Diagnostic depth
Detection
- Error will be internally in %HT2KTLSU over CJ125-Analyse-IC identified
Possible cause
- Heating line primary oxygen sensor LSU defect - Short circuit to voltage supply