Catalytic Converter Replacement
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Catalytic Converter Replacement
I have been getting a CEL P0420 for low cat efficiency bank 1 on my 2002 Ford Escape
V6. The truck runs fine otherwise. I have ran two loads of Cataclean and the light keeps coming back a few days after CEL reset so I am pretty sure one of cats is done. I am going to replace with an aftermarket cat. My question is, with this code, do I need to replace the front exhaust manifold cat or the rear manifold cat?
V6. The truck runs fine otherwise. I have ran two loads of Cataclean and the light keeps coming back a few days after CEL reset so I am pretty sure one of cats is done. I am going to replace with an aftermarket cat. My question is, with this code, do I need to replace the front exhaust manifold cat or the rear manifold cat?
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Joined: Jan 2002
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From: suburban atlanta
I don't know the code, but a 'bank' failure means one side of the engine or the other. Bank 1 is the rearward side, for cylinders 1-2-3, and bank 2 is the forward side, cylinders 3-4-5.
So, it would be the rearward cat. The O2 sensors are labeled for each bank also, and the 'after cat' sensor would be sensor 2. It is just to monitor the efficiency or effectiveness of the converter. It expects to see 'catalyzed' exhaust, and will signal if the output is not good.
I would consider checking the forward side cat also, as they both have the same mileage and were likely fed close to the same exhaust mix. If the plugs go bad, they'll feed raw gas and melt the cats, so you might find it close to failure also. I think the 2nd O2 reading can indicate how close it is to failure. A good shop will be able to pull the O2 output for comparison.
tom
So, it would be the rearward cat. The O2 sensors are labeled for each bank also, and the 'after cat' sensor would be sensor 2. It is just to monitor the efficiency or effectiveness of the converter. It expects to see 'catalyzed' exhaust, and will signal if the output is not good.
I would consider checking the forward side cat also, as they both have the same mileage and were likely fed close to the same exhaust mix. If the plugs go bad, they'll feed raw gas and melt the cats, so you might find it close to failure also. I think the 2nd O2 reading can indicate how close it is to failure. A good shop will be able to pull the O2 output for comparison.
tom
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