Kia 2004.5 Spectra Service Technical Training page 137

2004.5 Spectra Technology
NARROW RANGE HO2S
Driveability
The 2004.5 Spectra only uses this type (Zirconia) of
HO2S for its sensor 2, or rear sensor. It's mounted
after the catalytic converter in the rear exhaust pipe.
Sensor 2 provides feedback to the PCM estimating the
converter's oxygen storage capability and monitoring
catalytic converter efficiency. The rear sensor signal
will also fluctuate in the 0 to 1V range. Once the
catalyst has reached its operating temperature, the
sensor's output should change minimally because the
oxygen fluctuations are smoothed by the oxygen
storage capacity of the catalytic converter.
If the sensor 2 signal fluctuates similar to the front
HO2S, it's an indication that the catalytic converter is
not at operating temperature or is malfunctioning due
to aging, poisoning, or misfiring. A signal graph, such
as above, can be obtained using the Hi-Scan Pro. The
exhaust should be checked using a 4- or 5- gas analyzer.
19