GxT Ferret 54 ENGINE DIAGNOSTIC CENTER - Manual (Page 68)

O2 SENSOR TEST
Press FUEL SYSTEM - GAS ANALYSIS,
SELECT
O2 Sensor Test , and press NEXT.
Many emissions problems are the fault of a
lazy or defective O2 sensor or its
connections, so testing the O2 sensor first
can save time.
Warm up the engine before running the test,
so that the O2 Sensor will be active.
Connect the Auxiliary Meter Lead to the O2
sensor output wire, either by backprobing or
using jumper wires. Avoid piercing insulation
where moisture may enter and cause
corrosion. Refer to the vehicle wiring
diagrams to identify the output wire. Some
vehicles use a heated sensor which requires
additional wires.
The most common sensor is based on
zirconium. At the stoichiometric point (ideal
air-fuel mix) it will produce 0.45 volts. Above
that voltage indicates RICH and below
indicates LEAN.
6-3
A less common sensor is made from titania.
This material changes resistance in the
presence of oxygen and affects the voltage
of the oxygen sensor circuit in the opposite
direction of a zirconia sensor. A menu option
will allow you to designate the type of sensor
used in the vehicle being tested. Sensors
with a stoichiometric point other than 0.45
volts cannot be evaluated with this test.
The SELECT keys may be used to
alternately include or exclude the Gas
readings. Readings may be recorded for later
review by pressing the RECORD button.
Recording can be stopped by pressing
PAUSE or RECORD. Once data has been
recorded, restarting the O2 Sensor Test and
choosing
Examine will allow data to be
reviewed in a live playback mode, erased or
added to. In playback mode the PAUSE,
FAST FWD and REWIND keys operate like
a tape player.
While recording or reviewing measurements
in playback mode, NEXT may be pressed to
mark a screen to be printed later in the
REPORT. Marked data screens will show a
'
N
' diamond.
A
FEW VEHICLES WITH TITANIA
SENSORS MAY USE A POINT OTHER THAN
0.45
VOLTS TO INDICATE STOICHIOMETRY
. I
N SUCH
CASES
, C
ROSSINGS AND
% D
UTY
R
ICH ARE
INVALID
,
AND THE OUTPUT VOLTAGE MAY
EXCEED THE RANGE OF THIS VOLTMETER