A Chevrolet km car with a mileage of over 210 thousand and equipped with 2.4L. User response: the engine and ESP fault lights on the meter are bright. Fault diagnosis: TECH2+CANDI check EBCM set: 00040, right front wheel speed sensor circuit; ECM set: P0328, KSI circuit high frequency; AWD setting: C0561, system closed information has been stored, rear drive system. The car has been running 213213km, analysis of the right front wheel bearings may cause abnormal wheel speed signals due to wear and corrosion, thus setting up 00040 and C0561 fault codes, brake anti lock and rear drive system suspension work; and the engine set knock fault should not be directly related to the above fault. Check the maintenance manual, the fault code P0328 means the detonation sensor (KS) circuit voltage high - cylinder group 1; the condition of setting the fault code P0328 is that the engine control module detects that the detonation sensor signal voltage is higher than the normal engine noise level. The detonation sensor (KS) is a piezoelectric device that generates an AC voltage of different amplitude and frequency according to the degree of mechanical vibration of the engine. By monitoring the detonation sensor signal, ECM determines whether deflagration and ignition detonation exists. If the detonation sensor system confirms the existence of excessive detonation and engine control module The spark timing will be delayed immediately until the knock is controlled. To distinguish between engine normal noise and ignition detonation, the engine control module samples the knock sensor signal. In the absence of cylinder knock, the engine control module samples the knock sensor signals at a specific time interval at different engine speeds and loads. The sample is used to determine acceptable range of normal engine noise. The test car found that the start and acceleration process did not hear the crisp "click, click" detonation noise; check the detonation sensor plug has no water, the detonation sensor is installed correctly, no loosening or overfastening problems. Because of the simple structure of the detonation sensor and high reliability, the possibility of damage is very small. According to the mileage of the vehicle, it is possible to analyze the wear and loose of the engine support, suspension or other chassis components. The check chassis found that the bearing of the right middle transmission shaft on the front axle transfer box has been seriously worn, loose and loose, and the clearance is very large. Misreport detonation and set up P0328.