2003 Porsche Boxster Base, AutomaticFACTORY OEM SERVICE PROCEDURE

O2 Sensor Circuit Slow Response

Diagnostic conditions 

  • Air mass between 25kg /h and 120 kg /h
  • Oxygen sensing after catalytic converter is active
  • Basic adaptation has reached steady condition
  • No secondary air diagnosis
  • No fuel tank ventilation diagnosis
  • EVAP canister not highly loaded
  • No other oxygen sensor faults

Possible cause of fault 

  • Oxygen sensor faulty

Affected terminals 

None

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.