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P0420 and P0430 on Focus Mk3 1.6 Petrol 125


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A few weeks ago whilst out on a motorway the engine light came on. When home I hooked it up to the scanner and had a P0420 code. 

I got some cat cleaner and put that through and reset the code. 

3 weeks go by and again whilst on a long run up pops the engine light. This time I have got P0420 and P0430 with another P0430 stating malfunction confirmed. 

Copy and paste of both below: - 

Code: P0430 - Catalyst System Efficiency Below Threshold (Bank 2)
Code: P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

Code: P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

 - Confirmed - malfunction is confirmed 

I have done some live readings. 

O2S11, O2S12, O2S21 and O2S22 are all fluctuating between 0.1 and 0.9 with about 1 to 2 seconds gap. 

Two pictures below. one is at idle and the other is at 2500 rpm. 

From looking at this data can I come to any reasonable conclusion as to what I need to replace?


Thanks all




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