Oxygen Sensor - UNI-T UT105 Operating Manual

Measurement Operation(25)
To be adapted to the provisions for low injection and fuel
saving in the early period of the eighties, the computer-
controlled regulators were installed in the automobile
and the sensors provided the computer with some data
required. The multimeter is an effective tool for the
detection of the operation of a sensor.

1.Oxygen Sensor

The oxygen sensor is used to test the oxygen content in
the exhaust, giving rise to an appropriate voltage or
resistance. A low voltage (high resistance) means a too
high oxygen content in the exhaust, while a high voltage
(low resistance) means a too low oxygen content. The
computer regulates the ratio between the air and the fuel
according to the high or low voltage. There are normally
two types of oxygen sensors: the zirconia and titania sensors.
(Refer to the different external properties of the two types
for the details.)
Testing Procedure:
(1) Move the oxygen sensor out of the automobile.
(2) Set the rotary switch to 200
LCD connect terminal, insert the red test lead into
the terminal and the black one into the COM terminal.
(3) Connect the black test lead probe of the meter to the
ground terminal (i.e. cold end) of the sensor.
Warning:
l If the sensor has a 1- or 3-lead outlet, the ground
terminal is its shell.
l If the sensor has a 2- or 4-lead outlet, the ground
terminal is its special wiring.
Model UT105: OPERATING MANUAL
. As prompted at the
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