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Q: what's the solution for the po420 code,if i just changed the umstream a/f sensor on 1999 Toyota Camry

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
i drove for one day and the check engine light came on, had it checked and cleared, it came back on the next day.
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
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Hi there: That is the code for the Catalytic Converter, my friend, and you should not have changed the A/F sensor. This code is the "Kiss of Death" for vehicles and if you do not get it replaced, then it will cost you a lot of money down the road. And also some pieces of the converter will get into the exhaust system and that will cost you a lot of money to get it fixed.

That is the converter code for sure. So take it to either NTB, Midas or some place like that. DO NOT take it to your dealership since they will charge you a lot of money for to diagnose it and replace it. DO NOT take it to a gas station, but you can take it to a reputable mechanic to get it done right. Have the mechanic do a FULL diagnostic test on the Check Engine light to make sure that it IS the converter. If it is, the cost to get it done SHOULD run you between $700-$900 depending on where you go. If you go to a dealership or a gas station, they will run you close to $2,000 or so.

When I took my car today to Midas, they will charge me close to $850 to get it done and to get it done right, compared to the gas station near my house who was going to charge me close to $2,000 for that.

Hope this helps.

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