1998 O2 sensor

[Len Sabatine]

At 12:44 PM 6/28/00 -0500, you wrote:

> >     If utilizing the 98 PCM OBD2 config , you'll need to utilize the Pre -
> > Post Ho2s on each side
> > of the engine since the PCM is calculating Bank to Bank Fuel Trim based on
> > all 4 sensors.
> >   Len
>
    About every 100 seconds the VCM compares the switching time intervals 
of the 4 HO2S,
it also uses the L&R Bank 2ndary HO2s to "Monitor" cat Oxygen Content Ratio.
In OBD2, if the VCM can't get all 4 switch " Expected" responses in"time" , 
then expect
at the very minimum  S hort T erm and L ong  T erm Fuel Trim Adjustments. 
There's
more , I'd say give the VCM what it wants and use the 4 Heated Oxygen Sensors.
All this information and more is defined in S.A.E. J1850 Specification [s] 
, Heated
Oxygen Sensor  Tests and Diagnostics. Failure of the heater circuit can 
also cause
Scew of the Fuel Trim Adjustments. This is the basics , gets more 
complicated  going
forward !

  Len

>Can someone tell me if the after cat O2 sensors are used for any actual
>engine calibrations or not on the 96-00 engines. Or do the after cat sensors
>just throw a trouble code if there is something out of whack with the
>catalytic converter?
>
>Thanks
>Paul Washburn
>lpwcruzr at netzero.net
>
>
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