Closed Loop Air/Fuel Ratio Control At Limit - System Too Lean
Closed-loop fuel trim hit its rich correction limit because mixture is structurally too lean. Likely vacuum leak, low fuel pressure, or contaminated MAF.
Affected components
- Intake system
- Fuel pressure regulator
- Mass air flow sensor
Common causes
- High likelihood: Vacuum leak
Possible symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.