LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2012 >> Forester XT Premium >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (Diagnostics) (H4DO) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) >> DTC Detecting Condition
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1): DTC Detecting Condition

DIAGNOSIS PROCEDURE

Step Check Yes No
1 CHECK EXHAUST SYSTEM. 
NOTE: Check the following items.
  • Loose installation of front portion of exhaust pipe onto cylinder heads
  • Loose connection between front exhaust pipe and front catalytic converter
  • Damage of exhaust pipe resulting in a hole
Is there any fault in exhaust system? Repair the exhaust system. Replace the front oxygen (A/F) sensor. < refer to FRONT OXYGEN (A/F) SENSOR . >