OBD-II FAULT CODE
P1131

Lack Of HO2S Switch - Sensor Indicates Lean

Reference information for P1131. Because this is manufacturer-specific, confirm the exact definition for the vehicle before using the diagnostic guidance below.

Manufacturer-specific code

This code can have different meanings depending on vehicle make, model and year. Treat the definition below as a reference and confirm it with OEM service information before diagnosis or repair.

PowertrainSystem
Fuel trim / lean conditionCategory
MediumSeverity
  • Check Engine light
  • Poor drivability or reduced fuel economy depending on fault
  • Rough idle
  • Hesitation
  • Higher fuel trims
  • Vacuum/intake leak
  • Dirty or faulty MAF/MAP sensor
  • Low fuel pressure
  • Exhaust leak before O2 sensor
  • Scan all modules and record freeze-frame data before clearing codes
  • Check battery voltage and related fuses
  • Check fuel trims at idle and under load
  • Smoke-test intake system
  • Inspect MAF/MAP data and fuel pressure
  • Repair intake/vacuum leaks, clean/replace faulty sensor, correct fuel pressure or exhaust leak
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Disclaimer: Information is provided for general guidance only and may not apply to all vehicles. Always consult a qualified technician.