Oxygen Sensor - UNI-T UT106 Operating Manual

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 . As prompted at the
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.
(4)
Connect the red test lead probe of the meter to the
signal terminal (i.e. hot end) of the sensor.
If the sensor has more than 3 leads, what is used in
the automobile is a heat oxygen sensor, which has
2 hot ends. Refer the positions of the hot ends in
various kinds of automotive manuals.
At this time, connect the red and black test lead
probes respectively to these two hot ends. Compare
the readings with the specifications in the operation
manual provided by the manufacturer.
Model UT106: OPERATING MANUAL
44