Fault phenomenon
    A SUV-Highlander, at 40 ~ 60km / h speed (engine speed 1000 ~ 1200r / min) when driving, sometimes the whole body vibration, when the speed increases or decreases when the vibration disappears. The vibration is similar to the vehicle when the vehicle through the slowdown with the road when the whole body issued by the jitter. The conditions of vibration and the road does not matter, even in the flat wide road sometimes occur. The frequency of vibration is not high, the vehicle may be used only once a day.
    Failure analysis
    The vibration is generated by the vibration source, through the resonance system to amplify the vibration, and then transmitted through the transmission system, and then reflected in the vibration of the specific vibration of the situation. Visible vehicle vibration involves many factors, so it is difficult to judge. This paper describes the use of measurement tools to measure the frequency of vibration of the vehicle, and then according to the measured frequency through the theoretical calculation to infer which part of the system has a problem, and finally through the OBD data and vehicle road test to confirm the previous, thus forming a The well-established diagnosis of vehicle vibration failure is of great help to us to shorten the diagnosis time and improve the accuracy of the diagnosis.
    SUV-Highlander is the engine front 4WD vehicle. The car traveled about 10,000 km, without any accident and vehicle overhaul records. Check the condition of the tires first: the four tires are the same as the tire's air pressure at the standard value. And then carry out transposition on the tire, test failure did not eliminate. After the replacement of the four models with the tires, the fault still exists. So the initial judgment of the fault and the tire is not much relationship. And four rounds of positioning data, within the standard data range. Check the chassis and suspension section: Make sure that the drive shaft is installed correctly and that the fastening bolts between the drive shaft and the frame are normal and that the cross shaft of the drive shaft is not abraded. Since there is no abnormality in the drive shaft from the outside, replace the drive shaft of the same type, but the fault still exists. In addition to check the engine foot rubber and exhaust pipe installation, but also normal, there is no loose. Also checked the amount of ATF of the transmission, normal, the color was pink, and not black.
    Troubleshooting
    We did not see any problems with the control of the engine and the transmission after the external inspection did not find the abnormality. The car uses a V6 displacement of 3.5L engine, the occurrence of vibration and load does not matter. First use the Toyota dedicated OBD to detect air-fuel ratio and fuel injection signal, within the standard range, and with the same model of normal vehicle data comparison is almost the same. Replace the engine ECU (engine and transmission control share an ECU), the vehicle's failure still exists. The drive in the form of the engine front four-wheel drive, as shown in the figure.