ZackR

Hi guys, first post here. I was wondering if there are any vacuum diagrams available online. I've got a '96 Sable 3.0 and pulling a 430 code. I know this can also mean a bad CAT, but I can hear the leak (just can't SEE it). It's not affecting performance or mileage, I just would like to take care of it before it goes in for PA emissions.

Thanks

tbird100636

If there is an exhaust leak before or through an O2 Sensor, this code can set. Also, a bad downstream O2 sensor can cause this. But you have two upstreams abd two downstreams on your car. If you had a scan tool with a full data display you could watch the upstream and downstream O2 sensors work. You should see the upstreams switching continuosly and the downstreams switching rarely. If the downstreams are switching the same amount as the upstreams you either have a bad O2 sensor or the cat is bad. Try the downstream O2 sensor first. If they still switch the wrong way then you have a bad cat. If the switch the right way then you're all set. Are you sure its a vacuum leak??? If it has a plugged up cat it will cause a loud hiss similar to a vacuum leak and the car will run poorly or stall. This is from the excessive backpressure.

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ZackR

I don't have a full scan tool, so I can't be completely sure of yet. It isn't having an effect on performance, which kind of makes me think it is a vacuum leak.

SHOZ123

Diagnostic Trouble Codes (DTC) P0430 and P0431 indicate that bank 2 catalyst system efficiency is below the acceptable threshold.

Internal deterioration of a catalytic converter is usually caused by abnormal engine operation upstream of the catalyst. Events that can produce higher than normal temperatures in the catalyst are particularly suspect. For example, misfiring can cause higher than normal catalyst operating temperatures.

Possible causes:

Use of leaded fuel.
Oil contamination.
Cylinder misfiring.
Damaged HO2S.
Damaged ECT sensor.
Downstream HO2S wires improperly connected.
Fuel pressure too high.
Damaged exhaust system pipe.
Damaged exhaust manifold.
Damaged muffler/tailpipe assembly.
Damaged catalytic converter