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VolvoDan, ASE Certified Technician
Category: Volvo
Satisfied Customers: 10
Experience:  ASE L1 and Volvo Certified Master Technician
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Have had multiple check engine codes on a 2002 volvo S80

Customer Question

Have had multiple check engine codes on a 2002 volvo S80 with 123,000 miles: P0420 and P0430. First time both front and rear oxygen sensors were replaced. Second time catalytic converter replaced. Third time they searched and found some kind of missing block plug which was replaced and then were concerned that the vapor box might be plugged up but pressures were checked and were ok. Now engine light back on for fourth time. Have not been able to have codes checked again yet. Ideas or concerns?
Submitted: 7 months ago.
Category: Volvo
Expert:  Eric replied 7 months ago.


Ok, air intake and vacuum hoses should be checked for any leaks, and exhaust checked for leaks. If not found, catalytic converter unit should be replaced. I suspect the converter has been the issue the whole time. This is the most common cause of these codes.

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Expert:  Eric replied 7 months ago.

I noticed we have not yet resolved your concern you asked about. I would sure appreciate it if you would reply so I can offer my skills and knowledge and repair guide access to help as best I can.
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Customer: replied 7 months ago.
Eric, your response suggests everything that has already been checked and replaced. We have a new converter, oxygen sensors, and hoses and exhaust have been checked multiple times. My question is what else could it be?
Expert:  VolvoDan replied 7 months ago.

I know I am coming in on this late, but has the ECM been removed for 10 minutes or more so that the adaptive values could be reset?

Customer: replied 7 months ago.
Dont know for sure
Expert:  VolvoDan replied 7 months ago.

I would get the codes checked, it could be on for something other than these items. Were aftermarket parts or Volvo genuine parts used for the repairs?