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honda accord speedometer problems
Possible causes of the failure are:
1) The vehicle speed sensor is faulty or the sensor circuit is poorly connected.
2) The speedometer drive circuit is faulty.
3) The speedometer is faulty.
Troubleshooting method :First, conduct visual inspection: check the relevant line of speedometer. The circuit is checked, and the circuit and connector are normal. Check the power and grounding of the speed sensor: unplug the speed sensor, sensor plug. After closing the ignition switch (ON), use a 12V test lamp to measure the voltage of the middle terminal (connected with the brown wire) of the vehicle speed sensor plug. If the test lamp is on, it indicates that the power supply of the sensor is normal; Measure the resistance and continuity between the grounding terminal (black wire) of the sensor plug and the grounding, indicating that the sensor grounding is good.
Check the signal voltage of the vehicle speed sensor: connect the plug of the vehicle speed sensor, connect the signal terminal of the sensor with a wire, and lead the wire terminal into the cab. Measure the signal voltage of the sensor while the vehicle is driving. The signal voltage changes from 0.5 to 1. 25V. Under normal conditions, the vehicle speed sensor shall output a pulse voltage varying from 0 to 5V. Therefore, according to the measured sensor signal voltage, it is preliminarily determined that the vehicle speed sensor is faulty.
As the engine fault warning lamp on the instrument panel has been on, it is necessary to check the engine fault code to confirm the fault. Remove the guard board under the right side of the cab, find the inspection socket of the engine ECU self diagnosis system, and jumper with wires. After closing the ignition switch (ON), the engine fault warning lamp on the instrument panel starts to flash, displaying a fault code of 17. According to the data, the fault corresponding to the fault code of 17 is the poor signal of the vehicle speed sensor. Remove the speed sensor, prop up one wheel, shift to low gear, observe the groove connecting the speed sensor in the transmission, and find that it rotates normally. It is ruled out that the rotor drive is triggered by the sensor signal at the transmission. The instrument panel has also been removed, and no abnormality is found. Therefore, it is determined that the fault is the speed sensor.
Troubleshooting measures:Replace the vehicle speed sensor with a new one. The speedometer works normally and the fault is eliminated. Then disconnect the negative cable of the battery for about 10s to clear the fault code, and the engine fault warning lamp on the instrument panel will no longer flash.
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