P0420 bank 1 code


Asked by bjtrans26 Aug 24, 2011 at 08:54 PM about the 1998 Lincoln Town Car Signature

Question type: Maintenance & Repair

my check engine light is on and it shows the P0420 code for bank 1. My car has 4 converters on it and the temp guage goes up when it sits for awhile idling. Was wondering if anyone thinks it is a bad Cat. Conv. and if there is a way to tell which one of the 4 are bad.  It also now has a cylinder #4 misfire.  Any help appreciated.

5 Answers

Mike Bonnell

Bank One is Passenger Side - Blocked cat will cause overheating and misfires - #4 is also on The Passenger Side You usually replace the banks in pairs - So replace the Both On the passenger side and replace both O2's also to protect your INVESTMENT in Cat's

2 out of 2 people think this is helpful.

Thanks for the info, I appreciate it. Will I do any major damage driving it until I can get the money to fix it?

1 out of 1 people think this is helpful.

Your O2 sensors are fouled with carbon from the cylinder #4 misfire. Fix the misfire first then as suggested, replace both two O2 sensors on that side. Each sensor is about $50 dollars. A new cat is about 1,000 to 1,200 new. Start with the misfire and O2 sensors first. Unless your ignored the misfire for a long period of time. This would cause the cats to be fouled with excess carbon and lose their efficiency to do their job. Good Luck

2 out of 2 people think this is helpful.

Magnaflow cats in pairs for around $200-$250 for 96 tc

1 out of 1 people think this is helpful.

EASTERN CATALYTIC Part # 30383 ECO II Direct Fit and EASTERN CATALYTIC Part # 30384 ECO II Direct Fit at RockAuto for 148$ Canadian each! ;) (not legal for California or NY though)

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