Diagnosis and analysis of sensor failure of the ho

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Diagnosis and analysis of automobile sensor fault and key points of solution

people can control the operation of the experimental machine through the console. 1. The failure of the computer power line will deteriorate the performance of the automobile engine and reduce the economy. Therefore, before the replacement of the automobile computer, you should first check the power line of the computer. (the power cord should include the ground wire to be a complete power cord)

2. If the voltage signal of the oxygen sensor is higher than the standard value, it may be that the sensor is polluted. In many cases, it will enrich the air-fuel ratio

3. If the voltage signal of the oxygen sensor is lower than the standard value, the sensor may have a fault, which will cause the air-fuel ratio of the engine to become lean

4. When checking the oxygen sensor, you must use a digital multimeter or oscilloscope

5. If the heater of oxygen sensor fails, it may prolong the open-loop working time of the engine and increase the fuel consumption

6. The performance of the engine coolant temperature sensor can be checked with a digital meter or an analog meter

7. Ect electricity of some computers 2. The experimental machine should be regularly verified once a year by a technical institution authorized by the legal institution. In the circuit, an internal resistor will be controlled at a certain temperature of the engine to change the voltage on the sensor. If the voltage at this time is abnormal during the measurement, it does not mean that the sensor is faulty

8. The test of engine coolant temperature sensor and intake air temperature sensor can use the same operation procedure. The only thing to note is that their temperature change curves are different, so there will not be the same voltage signal at the same temperature

9. When the throttle is open and the voltage signal of the throttle position sensor is checked, the stability of the sensor can be checked by shaking with appropriate force. This method is very effective for some circuit virtual faults

10. Many four wire throttle position sensors contain an idle position switch, which is used to provide the engine control unit with the working state information of the engine when the throttle is in the idle position

11. In some cases, the fixed screw of the throttle position sensor can be loosened and the housing of the sensor can be turned to adjust the voltage signal when the throttle is in the idle position

12. If the output of the manifold absolute pressure sensor is a frequency signal, it cannot be tested with an ordinary multimeter

13. Many manifold absolute pressure sensors output voltage signals converted by atmospheric pressure. Such signals can be checked by turning on the ignition switch. (this method can only prove that the sensor can work. If the output accuracy decreases, it cannot be checked by this method.)

14. When checking the output voltage signal of the manifold absolute pressure sensor, there should be a certain degree of vacuum in the sensor. In most cases, it can be judged by detecting its output signal every 10 kPa

15. When measuring the voltage signal of the wing plate intake flow sensor, you can check the voltage value and continuity of the output signal when the wing plate of the sensor changes from fully closed to fully open

16. Some thermal resistance or air intake flow sensors provide voltage signals with frequency changes by the engine computer. Such sensors can only check their voltage with a multimeter that can test the frequency

17. The voltage signal of the EGR valve position sensor will vary from 0.8V when the valve is closed to 4.5V when the valve is fully open

18. The computer uses the signal of the speed sensor to control the clutch of the torque converter. 4. The experiment with prompt can improve the speed, promote the efficiency of gear shifting, and the data acquisition of the driving computer

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