Computer problem
1996 Mercury Sable 6 cyl Front Wheel Drive Automatic 142000 miles
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a trouble code of P0430 came up. what do i need to check for in bank 2. i would like some insight on this subject before i take the car to a exhaust shop.

Hi there.


The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

A code P0420 may mean that one or more of the following has happened:

Leaded fuel was used where unleaded was called for
An oxygen sensor is not reading (functioning) properly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings

mark (mhpautos)

i drive like 2 minutes to work, would driving a very short distant make it go off because the car doesnt warm up.

Hi there,

The short drive in it's self should not make it go off, i feel that the up stream O2 sensor may be clogged and is causing your problem,

Mark(mhpautos)