40
3.2.10
Lambda
The Lambda, or Oxygen Sensor is generally installed on the exhaust pipe, before the catalytic converter. It is a
feedback sensor used to sense the oxygen content in the exhaust gas, so that the ECM can judge the combustion
situation in the combustion chamber and adjust the fuel supply of the engine.
There are several types of oxygen sensors: titanium oxygen, zirconium oxygen, and front & rear dual oxygen sensors;
the signal switching frequency is about 1 Hz, and it can only work when the temperature is normal. The voltage is
high when the mixture is thick, and the voltage is low when the mixture is thin.
Use a BNC to banana cable, one end is connected to channel 1 of the oscilloscope, the other end is grounded with
the black plug, and the red connector is connected to the signal line (pre-oxygen) of the oxygen sensor with a needle.
Use a BNC to banana cable, connect one end to channel 2 of the oscilloscope, ground the black plug on the other
end, and use a needle to connect the red connector to the signal line of the oxygen sensor (rear oxygen, if there is
no rear oxygen sensor, no test is required). If you want to measure current, connect the BNC end of the current
clamp to channel 3 of the oscilloscope, and clamp the clamp on the heating wire.
Use ATO oscilloscope to test the oxygen sensor, the specific operation is shown in Figure 3-20:
Figure 3-20 Lambda (oxygen sensor) test
The following picture is the actual measurement diagram of a certain model of oxygen sensor:
Summary of Contents for ATO1000 Series
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Page 2: ...Version Info Version Date Remarks V1 0 2020 06 ...
Page 52: ...Chapter 3 Automotive Test 49 Figure 3 30 Electronic fuel pump test ...
Page 71: ...68 Figure 3 49 K line test ...
Page 79: ...76 Figure 3 57 Mazda 6 Cylinder internal pressure measurement ...
