2007 Boxster getting P0421 Fault

[Salvos5]

The car has 68,000 miles on it and runs great but I'm worried about failing my emissions test. Does this fault mean I will have to change my catalytic converters? Thanks!

 

 

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[Loren]

 

Fault 0421 - Catalytic conversion

 

Possible fault causes:
- Oxygen sensors in front of and behind catalytic converter swapped (position in exhaust assembly)
- Valve lift error
- Aged oxygen sensor behind catalytic converter
- Catalytic converter faulty (pre-catalytic conversion rate too low) If an aged oxygen sensor (oxygen sensor signal behind catalytic converter, dynamism) is detected together with this fault:
- remedy the fault "Oxygen sensor signal behind catalytic converter, dynamism" first,
- Then check if this fault - catalytic conversion - has been entered again.

 

IMPORTANT
If the primary catalytic converter is faulty, check the main catalytic converter for damage and also replace it if necessary.

 

What tool are you using to read faults?

If is is not a Porsche specific tool (like Durametric or PIWIS) then you may not be getting all the Porsche fault codes.

[Salvos5]

 
Fault 0421 - Catalytic conversion
 
Possible fault causes:
- Oxygen sensors in front of and behind catalytic converter swapped (position in exhaust assembly)
- Valve lift error
- Aged oxygen sensor behind catalytic converter
- Catalytic converter faulty (pre-catalytic conversion rate too low) If an aged oxygen sensor (oxygen sensor signal behind catalytic converter, dynamism) is detected together with this fault:
- remedy the fault "Oxygen sensor signal behind catalytic converter, dynamism" first,
- Then check if this fault - catalytic conversion - has been entered again.
 
IMPORTANT
If the primary catalytic converter is faulty, check the main catalytic converter for damage and also replace it if necessary.
 
What tool are you using to read faults?
If is is not a Porsche specific tool (like Durametric or PIWIS) then you may not be getting all the Porsche fault codes.

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[Salvos5]

I'm using a I960 scanner by Icarsoft, the Porsche guy I take the car to confirmed the fault. Is it hard to change the oxygen sensor? Thanks


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[JFP in PA]

5 hours ago, Salvos5 said:

I'm using a I960 scanner by Icarsoft, the Porsche guy I take the car to confirmed the fault. Is it hard to change the oxygen sensor? Thanks


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No, it is not particularly difficult, you will need an appropriate sized wrench that can get to it (space is restricted), but the sensors unplugs from the harness and unscrews.  You will need to torque the new one in to the correct spec however.