P1153moderate severityPowertrain

Air/Fuel Sensor Circuit Response Bank 1 Sensor 2

on 2000 Toyota 4Runner 2.7L I4 · 4WD

What this code means

The downstream A/F sensor is switching too slowly.

Symptoms

  • CEL
  • Failed emissions
  • Poor efficiency
  • Rough idle

Common causes

  • Aging sensor
  • Degraded catalytic converter
  • Exhaust leak
  • Wiring damage

Diagnostic steps

  1. Monitor sensor switching
  2. Test catalytic efficiency
  3. Check exhaust leaks
  4. Inspect wiring

Repair notes

Replace sensor or diagnose catalytic converter.

Other Powertrain codes on this vehicle

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