What's Wrong with an Abnormal Tachometer?
1 Answers
Common causes of the malfunction include the following: 1. The speedometer in the vehicle's instrument cluster may be faulty, causing the needle to stop moving. 2. The vehicle's wheel speed sensor may be malfunctioning, leading to the tachometer's failure. 3. The vehicle's mileage sensor may be defective, resulting in the tachometer not functioning. Fault diagnosis methods: 1. Disconnection method. When the readings of automotive electrical instruments are abnormal, and analysis suggests that there may be a grounding fault in the sensor or the wiring between the sensor and the indicator instrument, the disconnection method is often used for inspection. 2. Grounding method. When the readings of automotive electrical instruments are abnormal, and analysis indicates that the sensor may have poor grounding or damage, or there is an open circuit in the wiring between the sensor and the indicator instrument, the grounding method is commonly employed for inspection. By grounding the relevant terminals with a wire, the cause and location of the fault can be determined. 3. Short-circuit method. When all other electrical instruments are functioning normally, and only the instruments connected to the voltage regulator (such as the fuel gauge, electromagnetic water temperature gauge, etc.) are not working, the short-circuit method can be used for inspection. Short-circuit the input and output terminals of the voltage regulator with a wire. If the needle of the instrument connected to the voltage regulator immediately deflects, it indicates an internal fault in the voltage regulator.
