chevy silverado speedometer too fast

2023-03-08

The first road test, using the manual mode and looking at the data, concluded that the transmission originally did not have 2 and 3 gears, that is, directly shift from 1 to 4 gears (2 and 3 gears do not feel shift and do not slip).

(1) Decode with decoder (x431) first. The fault code of transmission is:① P0873 Transmission oil pressure closes the high pressure of circuit C;P1751 shift solenoid valve A performance; P2714 transmission fluid pressure control solenoid D performance or stuck off.

(2) After reading the data of this fault code, we learned that P0873 shift solenoid valve controls the transmission hydraulic control valve by opening or closing the transmission hydraulic control valveThe hydraulic pressure of the speeder clutch controls its separation and combination to achieve gear shifting. Accurate control of transmission hydraulic pressure is very important for smooth shifting. The function of the transmission hydraulic pressure (TFP) sensor is to transmit the transmission hydraulic pressure to the transmission control module (TO U) in the form of electric signal, as a reference for the operation of the transmission hydraulic control solenoid valve. P1571 Shift solenoid valve controls the hydraulic pressure to the transmission clutch by opening or closing the transmission hydraulic control valve to control its separation and combination, thus achieving shift. The fault causes of this fault code include low transmission oil level, dirty transmission oil, mechanical fault of shift solenoid valve, circuit, connector or transmission control module (TCM) fault, etc. P2714 Shift solenoid valve controls the hydraulic pressure to the transmission clutch by opening or closing the transmission hydraulic control valve to control its release. And to shift gears. Accurate control of transmission hydraulic pressure is very important for dry and smooth shifting. The function of the pressure control solenoid valve is to control. Brake transmission fluid pressure. The causes of this fault code include the pressure control solenoid valve itself, circuit, connector, etc. At the same time, pay attention to the transmission. In some cases, the control solenoid valve failure is not due to electronic problems, but due to pipeline blockage or mechanical problems. Many times, just because the transmission oil is too dirty will cause many failures in this area.

(3) According to the above analysis and judgment, the transmission can be repaired. When checking the transmission oil, it was found that the oil was a little dirty and there was no burnt lake smell.

(4) Could it be that the solenoid valve gets stuck after the oil is dirty, and it doesn't work well?

(5) It happens that the TCM of the transmission is in the transmission itself. Is the oil circuit blocked or the TCM module faulty?

(6) Is the clutch slipping, or is the pressure in the middle oil circuit relieved?

(7) Of course, the possibility of oil circuit board cannot be ignored.