起动发动机之后仪表板的ABS故障警告灯一直点亮，车辆行驶时进行紧急制动

After starting the engine, the ABS fault warning light on the instrument panel has been lit, emergency braking is performed while the vehicle is running, the ABS control function fails, and all four wheels are locked. <br>Fault diagnosis and maintenance: connect the diagnostic instrument to perform self-diagnosis on the ABS system, and the result has two fault codes: fault code 01201 is the power supply voltage fault of the backflow electric pump, and fault code 00287 is the right rear wheel speed sensor is open or the positive pole Short circuit. Clear the fault code, but the above two fault codes cannot always be cleared. <br>Select the test menu of the actuator of the diagnostic instrument, and perform an activation test on the return electric pump. As a result, the return electric pump does not respond. The return electric pump is installed on the ABS hydraulic unit, which is directly supplied with working power by the ABS control module. The resistance value of the measured return electric pump is about 0.8Ω, which is within the standard value range. Conduct an energization test on the backflow electric pump, which can be operated. Check the ground wire of the return electric pump, normal. The above test results indicate that there is no problem with the backflow electric pump itself, and the failure is most likely caused by poor performance of the ABS control module. <br>Check the related problems of the right rear wheel speed sensor and measure the resistance of the right rear wheel speed sensor is about 1.1kΩ, which is within the standard value range. Remove the right rear wheel speed sensor, check the signal ring gear and working clearance, normal. Install the right rear wheel speed sensor, lift the vehicle, turn on the ignition switch, enter the data flow diagnosis menu, select the 001 data block, turn each wheel by hand, view the speed signal of the wheel, the result shows that the right rear wheel speed displayed by the diagnostic instrument is 0km / h, and the speed signals of other wheels are normal. Such faults usually have the following causes: damaged wheel speed sensor, poor wiring harness connection, and damaged ABS control module. For this purpose, an oscilloscope is used to measure the speed sensor of the right rear wheel, and the result is a sine wave pulse signal waveform. Perform the same waveform measurement on the left rear wheel speed sensor and compare it with the waveform of the right rear wheel speed sensor to confirm that the right rear wheel speed sensor is good. Unplug the harness connector of the ABS control module and check the connection to the right rear wheel speed sensor. The result is normal. In order to further determine the cause of the failure, the signal line of the left rear wheel speed sensor and the signal line of the right rear wheel speed sensor are connected together, and the left rear wheel is turned to view the data stream. As a result, there is still no right rear wheel speed signal. So far it is basically possible to judge that the ABS control module is damaged.<br>Check the power cable and ground wire of the ABS control module, normal. Remove the ABS control module, open the shell, and found that the internal circuit board is damaged. Replace the ABS hydraulic unit assembly (including the ABS control module and hydraulic valve body), and encode the new ABS control module to finish starting the engine, and the ABS fault warning light goes out normally. After the road test, the ABS control function returned to normal, and the overhaul work was completed.

The ABS fault warning light for the instrument panel is always on after starting the engine, the vehicle is under emergency braking while driving, the ABS control function is inoperative and all four wheels are stuck.<br>Fault diagnosis and repair: The connection diagnostic instrument for the ABS system self-diagnosis, the result has two fault codes: fault code 01201 content is the return of the electric pump supply voltage fault, fault code 00287 content is the right rear wheel speed sensor open or short-circuit to the positive pole. Clear the fault codes, but the two fault codes above cannever be cleared.<br>Select the execution element test menu of the diagnostic instrument and activate the return electric pump, resulting in the return electric pump not responding. The return-flow electric pump is mounted on the ABS hydraulic unit, which provides the working power directly by the ABS control module. The resistance value of the measured return electric pump is approximately 0.8 o, within the standard value range. The return electric pump is tested for power-up and the electric pump is operational. Check the iron line of the return electric pump, normal. The above test results show that the return electric pump itself is not a problem, the fault is likely to be the ABS control module poor performance caused.<br>Check the problems associated with the right rear wheel speed sensor and measure the resistance value of the right rear wheel speed sensor to be approximately 1.1k, within the standard value range. Remove the right rear wheel speed sensor and check the signal ring and operating clearance, normal. Install the right rear wheel speed sensor, lift the vehicle, switch on the ignition, enter the data flow diagnostic menu, select the 001 set of data blocks, turn the wheels by hand, view the speed signal of the wheels, the result of the diagnostic instrument shows the right rear wheel speed of 0km/h, while the other wheels of the vehicle speed signal is normal. Such faults are usually caused by damage to the wheel speed sensor, poor wiring harness connection, and damage to the ABS control module. To this end, the right rear wheel speed sensor is measured using an oscilloscope, resulting in a sine wave pulse signal waveform. The same waveform measurement is made on the left rear wheel speed sensor and compared with the waveform of the right rear wheel speed sensor to confirm that the right rear wheel speed sensor is good. Unplug the harness of the ABS control module and check the wiring connection to the right rear wheel speed sensor, with the result correct. In order to further determine the cause of the fault, the signal line of the left rear wheel speed sensor is connected to the signal line of the right rear wheel speed sensor, the left rear wheel is turned to view the data stream, and the result is still not the vehicle speed signal of the right rear wheel. At this point, it is basically possible to judge the abs control module damage.<br>Check the power cord and cable of the ABS control module, normal. Remove the ABS control module, open the housing, and find that the internal circuit board is burned. Replace the ABS hydraulic unit assembly (including abs control module and hydraulic valve body) and encode the new ABS control module to complete the starting engine and the ABS fault warning light goes out normally. Carry out road test, ABS control function returns to normal, repair work is completed.

After starting the engine, the ABS fault warning light in the instrument panel is on all the time. When the vehicle is in emergency braking, the ABS control function fails and all four wheels are locked.<br>Fault diagnosis and maintenance: connect the diagnostic instrument to carry out self diagnosis of ABS system, and there are two fault codes: fault code 01201 refers to power supply voltage fault of return electric pump, and fault code 00287 refers to open circuit or short circuit to positive pole of right rear wheel speed sensor. Clear the fault code, but the above two fault codes cannot be cleared all the time.<br>Select the actuator test menu of the diagnostic instrument and carry out the activation test on the reflux electric pump. As a result, the reflux electric pump does not respond. The return electric pump is installed on the ABS hydraulic unit, which is directly supplied with working power by the ABS control module. The resistance value of the reflux electric pump is about 0.8 Ω, which is within the standard value range. Power on test is carried out for the reflux electric pump, and the electric pump can operate. Check the grounding wire of return electric pump, normal. The above test results show that there is no problem with the return electric pump itself, and the fault is probably caused by the poor performance of the ABS control module.<br>Check the relevant problems of the right rear wheel speed sensor, and measure the resistance value of the right rear wheel speed sensor to about 1.1k Ω, which is within the standard value range. Remove the right rear wheel speed sensor, check the signal ring gear and working clearance, normal. Install the right rear wheel speed sensor, lift the vehicle, turn on the ignition, enter the data flow diagnosis menu, select 001 data blocks, rotate each wheel by hand, and check the vehicle speed signal of the wheel. As a result, the vehicle speed of the right rear wheel displayed by the diagnosis instrument is 0km / h, while the vehicle speed signal of other wheels is normal. These faults are usually caused by the following reasons: wheel speed sensor damage, poor wiring harness connection, ABS control module damage. For this reason, the oscillograph is used to measure the speed sensor of the right rear wheel, and the result has a sine wave pulse signal waveform. Carry out the same waveform measurement for the left rear wheel speed sensor, and compare with the waveform of the right rear wheel speed sensor to confirm that the right rear wheel speed sensor is good. Unplug the harness plug of ABS control module and check the connection with the right rear wheel speed sensor. The result is normal. In order to further determine the cause of the fault, connect the signal wire of the left rear wheel speed sensor with the signal wire of the right rear wheel speed sensor, turn the left rear wheel, and check the data flow. As a result, there is still no vehicle speed signal of the right rear wheel. So far, it can basically judge whether the ABS control module is damaged.<br>Check the power and ground wires of ABS control module, normal. Remove the ABS control module and open the shell. It is found that the internal circuit board is burnt. Replace the ABS hydraulic unit assembly (including the ABS control module and the hydraulic valve body), code the new ABS control module, start the engine, and the ABS fault warning lamp goes out normally. Carry out the road test, the ABS control function returns to normal, and the maintenance work is completed.