2004 Porsche Boxster Base, AutomaticFACTORY OEM SERVICE PROCEDURE

O2 Sensor Circuit Slow Response

Diagnostic conditions 

  • Engine speed between 1000 rpm and 3000 rpm
  • Engine load (relative air charge) between 12 % and 70%
  • Calculated TWC temperature greater than 350°C
  • Oxygen sensing system active

Possible cause of fault 

  • Oxygen sensor is dynamically inert

Affected terminals 

11/10 and 11/16

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.