DTC P0430 Catalyst System Efficiency Below Threshold (Bank 2) - Forums at Modded Mustangs
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post #1 of 3 Old June 19th, 2010, 05:49 PM Thread Starter
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DTC P0430 Catalyst System Efficiency Below Threshold (Bank 2)

My Check Engine Light is on in my 97 mustang 3.8L. It is throwing code P0430 which says it is Catalyst System Efficiency Below Threshold (Bank 2). What are the steps to fixing this? My car also takes a longer time to start than normal when it is cold. I have to hold the key to start position for like 6 seconds instead of a normal 1 to 2. Anyone have any ideas on what it could be? Also on my car I have been told two answers for which is bank 2. Anyone know for sure what side is 2? Also car is completely stock, no exhaust kit or anything.

Last edited by Vorek; June 19th, 2010 at 05:59 PM.
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post #2 of 3 Old June 19th, 2010, 06:19 PM
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I think that bank 2 might be the passenger side, but I'm not sure...It either means that, that rear 02 sensor is bad, or the 2 cats on that side are bad.

I went to school to be a mechanic, so I know what I'm talking about most of the time.

mods in the garage, slowly getting peppier.
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post #3 of 3 Old June 19th, 2010, 06:31 PM
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System Efficiency Below Threshold (Bank 2)

top Indicates Bank 2 catalyst system efficiency is below the acceptable threshold.
Use of leaded fuel
Damaged HO2S
Malfunctioning ECT
High fuel pressure
Damaged exhaust manifold
Damaged catalytic converter
Oil contamination
Cylinder misfiring
Downstream HO2S wires improperly connected
Damaged exhaust system pipe
Damaged muffler/tailpipe assembly
Retarded spark timing
Compare HO2S upstream and downstream switch rate and amplitude. Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which makes the switching frequency of the downstream HO2S very slow and reduces the amplitude of those switches as compared to the upstream HO2S. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal begins to switch more rapidly with increase amplitude, approaching the switching rate and amplitude of the upstream HO2S. Once beyond an acceptable limit the DTC is set
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