How to check the car oxygen sensor fault

Oxygen Sensor signal voltage as the most direct data to reflect the air-fuel ratio, is a very important reference data in fault diagnosis. In the closed-loop state, the working voltage of the oxygen sensor is generally 0.1-0.9V. Typically, maintenance personnel use an oscilloscope to detect or use an electronically controlled detector to read the corresponding data stream. These diagnostic devices are not available in many small and medium-sized repair shops.

In the absence of equipment, how will the oxygen sensor be repaired?

Use a light emitting diode to reach the signal output and ground. When the oxygen sensor works normally, the light emitting diode will flash once during each rich cycle and the signal voltage reaches the threshold voltage of 0.6-0.7V of the light emitting diode; if the mixture is too thin, the light emitting diode will not light; If the mixture is too rich, the light-emitting diodes will remain lit; if the oxygen sensor is damaged, it will generally light or not light.

Check the oxygen sensor is good or bad, there is a simple and convenient method, in the oxygen sensor signal output side and then from the battery cathode to introduce a power line, light-emitting diodes, so that it can form 0.6-0 in the loop. 7V analog signal voltage. According to whether the engine's working condition is improved, it can easily determine whether the oxygen sensor is damaged.

If the performance of the oxygen sensor is poor, it is not always necessary to replace it. Oxygen sensors, due to the effects of carbon deposits and lead in gasoline, will adhere to a gray-white substance on the outer wall during long-term work, namely the common name “lead poisoning”. This will affect the measurement accuracy. Therefore, the oxygen sensor should be restored. The method is as follows: Drive the vehicle, fix the joint in the first gear, press the accelerator in the end, and suddenly release the car after driving at high speed, and repeat it several times. Or remove the oxygen sensor and align it with the oxygen torch until it burns white.

Many people in the service use LEDs as test lights, but they are rarely used to detect oxygen sensors. Clever use of light-emitting diode 0.6 ~ 0.7V threshold voltage characteristics, can replace the oxygen sensor read data stream, set the oscilloscope operation. Can quickly check out the air-fuel ratio. In addition, the analog signal voltage of 0.6 to 0.7V can quickly diagnose the quality of the oxygen sensor.

Repeatedly in low-grade, high-load operating conditions, providing the best catalytic environment for the reduction of "lead poisoning" oxygen sensor. Under the high temperature ignition of the oxygen torch, it can also be quickly restored.