P0421

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AlbertoC215
Posts: 2
Joined: Wed Feb 06, 2019 5:19 pm

P0421

Post by AlbertoC215 »

Hi there,
I was getting this code (P0421) on my 2015 club with 39,000 miles. It has a RoadsterSport All Stainless Steel MX5 COMPLETE STREET EXHAUST COMBO...with CERAMIC installed @ 18,000 miles. I replaced both sensors with OEM parts and it was okay for 10 days. Today the "magic" light turns on again... It's no way the catalytic is bad... it's only 20,000 miles old???
Any clue?
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Brian
Site Admin
Posts: 11131
Joined: Tue Feb 15, 2005 11:44 am
Location: San Diego CA
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Re: P0421

Post by Brian »

Likely a sensor connection. Look at the pins in the plugs for the O2 sensors, are all the pins flush or did one get pushed deep inside the plug?
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
AlbertoC215
Posts: 2
Joined: Wed Feb 06, 2019 5:19 pm

Re: P0421

Post by AlbertoC215 »

Thanks Brian, I will check the connector...
Al
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