'98 Explorer EB V8 -- Check Engine Light?

Hello,

My Check Engine light came on the other day on my '98 Ford Explorer AWD
EB V8 with 66,000 miles. The vehicle runs fine, normal, and there was
no warning whatsoever, just the light.

I pulled into an Auto Zone and they scanned the computer and got a code
#PO420 (B1 below threshold), what ever that means??

The gal indicated my catalytic converter may be defective? Why would
this be, I didn't think catalytic converters just went bad without
something else going on? What should I be looking at here?

Any help and/or suggestions would be appreciated,

Steven

Hi Steven,

A quick google search found this at http://www.longbeachmuffler.com/faq.html

This has been a tricky problem for most mechanics and exhaust shops, When
diagnosing the problem with a scan tool. The code that comes up for an
inefficient Catalytic Converter is a PO420. This is an indication that the
Catalytic Converter is not doing its job properly but we have found that
this code could also occur if the Oxygen Sensor (O2 Sensor) or sensors
become faulty or lazy, We have also found that on the Jeep Cherokee, Subaru
Outback, Ford Explorer and Honda Accord, the factory tolerances that set off
the check engine light are very tight and an engine that has carbon buildup
in the combustion chamber will bring up the cylinder head temperature which
in turn brings up the Oxides of Nitrogen (NOX) and will set the light off.
In these cases we recommend a product on the market that has been working
well to cut down on the carbon build up and will reduce the dreaded check
engine light and PO420 code. The product is called BG44K- Total Deposit
Control Fuel Additive and can be purchased from us at our product link. A
good rule of thumb here is to make sure all components that we have
mentioned here have been checked before the Catalytic Converter is replaced.
There is nothing worse than spending hard earned money on a Catalytic
Converter and find out that the check engine light problem still exists.

"Steven Hilgendorf" > wrote in message
...
> Hello,
>
> My Check Engine light came on the other day on my '98 Ford Explorer AWD EB
> V8 with 66,000 miles. The vehicle runs fine, normal, and there was no
> warning whatsoever, just the light.
>
> I pulled into an Auto Zone and they scanned the computer and got a code
> #PO420 (B1 below threshold), what ever that means??
>
> The gal indicated my catalytic converter may be defective? Why would this
> be, I didn't think catalytic converters just went bad without something
> else going on? What should I be looking at here?
>
> Any help and/or suggestions would be appreciated,
>
> Steven

Steven Hilgendorf > wrote:
> My Check Engine light came on the other day on my '98 Ford Explorer AWD
> EB V8 with 66,000 miles. The vehicle runs fine, normal, and there was
> no warning whatsoever, just the light.

The code readers are just a first step in diagnosing the problem. I also
have a 98 with 96K miles. A few months ago the check engine light came on
with the same code. Diagnoses showed that one of the O2 sensors on an
exhaust down tube was flaky, ie, the voltage coming out of it was not
moving. A new one was screwed in and the check engine light has not
come on since.
Mark