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speedometer stuck at max
1.The problem must be the meter. It’s just that the stepping motor of the meter is a little faulty. The gear inside is stuck or the pointer and the stepping motor have a relative displacement. The mechanical zero position is on the upper side. At 0rpm, now because the stepper motor is stuck, its relative zero position has increased;
2. Cause analysis: the instrument itself is faulty, the power supply of the instrument or the grounding line is faulty; 3. The data bus of the instrument is faulty; preferred Check the fuse, no blown out is found, disassemble the instrument and measure the ground wire, if the wire harness is blocked, then the fault is obviously in the ground.
The first is the position of the relevant odometer of the vehicle. If there is a problem with the sensor, it is necessary to check the odometer position sensor. Second, some models belong to the speed controlled by the ABS sensor, so you need to check the ABS sensor. The third is the situation caused by the problem of the instrument, which needs to be repaired or replaced.
The speed of the car always does not reach the maximum value of the speedometer, which belongs to the international general industry standard. The standard of the car manufacturer for the speedometer stipulates that the actual speed of the car must not be higher than the speed of the meter, but the error is not allowed to exceed 7%. When the speedometer shows a speed of 100 kilometers per hour, the actual speed cannot exceed 100 and cannot be lower than 93. This is for safety reasons. At the same time, it is stipulated that there must be a reserved space for the maximum range of the speedometer, and the reserved degree shall not exceed 20%. That is to say, if the maximum speed is 100, the speedometer must be reserved to 120. The reason is that the maximum speed is measured on a level road. The maximum output value of the machine measured under the experimental conditions without wind, but in reality there is a downhill downwind situation, the speed of the vehicle must be higher than the theoretical value. In addition, there is another situation that the same model has different engine configurations. Using different speedometers will increase the manufacturing cost, so the speedometer will reserve a range for large-displacement engines, and use the same specification gauges for large and small displacement vehicles to save manufacturing cost.
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