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Chuck
Chuck, ASE Certified Technician
Category: Lincoln
Satisfied Customers: 2100
Experience:  Ford senior master,ASE Master L1 Certified
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Bank 2 catalytic converter the one with two cats..oxygen sensors

Resolved Question:

is bank 2 catalytic converter the one with two cats---and if i replace bank 2 cats do i need to replace oxygen sensors?
Submitted: 5 years ago.
Category: Lincoln
Expert:  Chuck replied 5 years ago.

Chuck :

If you are getting a code for bank 2 cat then the problem is the dual converter Y pipe

Chuck :






























ItemPart NumberDescription
15F250Dual Converter Y Pipe
25G203Exhaust System Flex Tube
35E212Three Way Catalytic Converter
45230Muffler
59F472Heated Oxygen Sensor
Chuck :

What I have circled is the bank 2 cat which is part of the y pipe part 5F250

Customer:

if i replace that do i need to change the oxygen sensors at the same time?

Chuck :

I would recommend the front ones

Chuck :

what are the codes you are getting?

Customer:

420

Chuck :

What I would recommend trying first before replacing the cat is replace the front O2 sensors and see if the PCM will take a reprogram and then see if the 420 comes back before replacing the cat

Customer:

what is downside if i continue to drive --car is performing great --

Chuck :

A lazy front O2 will also set the 420 code

Chuck :

The CEL will remain on and if you have to have emissions inspection in your state it will not pass

Customer:

mechanic did temp check and one of the two cats was off he said

Chuck :

Yeah what this code telss you is just the cat is not functiong correctly.The cat is actually an oven that lights by chemical reation to burn the unbirned HC's in the exhaust

Customer:

do not have emission check and is there any way to be sure it is the cat and not the sensor?

Chuck :

The only way to be sure is with an osiliscope

Customer:

who can do that?

Chuck :

See what the computer is looking at is the switch ratio between the front O2 and the rear O2.If they start coming close to matching this will set a P0420 and or P0430

Customer:

osiloscope test is that expensive and who can do?

Chuck :

Anybody that has an osiliscope and under stands how to read it could perform the test but that maybe more expensive than just replacing the sensor and trying that first.

Customer:

ok can i continue to drive the car until i get that down ...what could happen if i continue to drive...the cel is out now.

Chuck :

Nothing would happen.This particular codes would not hurt the car at all.The only problem that would cause a problem is if the cats were stopping up then you would see a big loss in power

Customer:

ok thank you

Chuck :

I have seen cars run for years with this code actually

Customer:

ok car runs great just seems to use a little more gas

Customer:

lots of power

Chuck :

you should be ok.I would try replacing the front O2 sensors

Customer:

any idea on cost?

Chuck :

Hold on and I will get the dealer price for you anyway

Customer:

good

Chuck :

The ford sensor $85 each and they would probably charge you an hour to hour and half to install them about $150

Customer:

they have t o replace two or just one?

Customer:

k thanks chuck ---just dont know what to do they want over 1000 f or the cat replacement

Chuck :

I would do both front ones.They are the main input for fuel control on this vehicle and if you have alot of miles on them this should improve the fuel mileage. The price would be around $300 for both replaced.

Customer:

ok thanks appreciate your advice! and i will accept

Chuck :

Thanks for using Just Answer

Chuck and 3 other Lincoln Specialists are ready to help you