Brake and speedometer pointer abnormal vibration

       Production plant: Toyota Motor Corporation
       License plate number: Crown MS125
       Production year: 1960
       Failure symptoms: abnormal sound generated near the front wheel, speedometer pointer occasionally vibrating abnormally
       Diagnosis: First unbundled brake system check, the results of the brake disc friction pad wear, but there are residues from the wear limit. Disc rotor does not vibrate. Wheel bearings are also not produce shoulder (stairs) shape wear, brake caliper moving parts also normal. The car is equipped with ABS system is currently very popular (anti-lock braking system). The sensor is removed, check the sensor-driven skp 900 v2.7 organization, the result is no exception. Once again, make a trial run, the results are very suspicious noticed the phenomenon, which is abnormal sound braking, the brake pedal and the speedometer pointer bounce vibration is synchronized to happen. This is the ABS system is considered abnormal, so unplug speed sensor connector, ABS stops the action, and then running test. After starting the engine, ABS brake system warning light lit up, indicating that the ABS system abnormalities. In this state the actual driving, no abnormal sound, the brake pedal does not rebound, completely normal. But the speedometer pointer still vibrating, it seems that the ABS system is abnormal. But if the electrical system is abnormal, then the ECU perception after, you should stop the action, while the warning lights should alarm. From the above analysis does not seem abnormal electrical systems, but there is some kind of failure associated with the speedometer, the actual inspection speedometer cable, driven gear, the results of the meter body, instrument cables are no exception, but in the back of the transmission is equipped with a gear box, filled with the rear wheel speed sensor ABS system. This is consistent with the front two wheel speed sensor, rear side of a wheel speed carsoft 6.5 sensor specifications. This sensor is mounted in the form of one of the driven gear box, a look removed, almost fell off from the gear shaft press-fitted, has two-thirds wear.
       Inferred from this situation, ECU can not normally get information on the drive shaft, which is ECU a while to get the drive shaft rotation signal, while they get the shaft stop signal, continuous input strange signal. ECU think rear wheel is locked state, issued a directive indicating lower rear wheel hydraulic brakes. That is, because the driven gear exception, so the speedometer pointer vibrate, and the brake pedal occur rebound. Front brakes produce different sounds at the same time, it should be the sound of the engine compartment incentives generated.
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