Shanghai throttle sensor voltage

Fault diagnosis: when you came to our factory for maintenance, you first detected the cylinder pressure, which was above 0.6MPa, indicating that there was no problem with the cylinder pressure. When measuring cylinder pressure, the removed spark plugs are all wet, indicating that there is a phenomenon of cylinder flooding. The decoder is used to extract fault codes, which are reported as "throttle position sensor open circuit or short circuit in positive pole", "air temperature sensor open circuit or short circuit in positive pole" and "coolant temperature sensor invalid or short circuit in positive pole". After clearing the fault code, the fault of reading the code again still exists, indicating that it is a hard fault. Read the code after replacing the sensor, and the fault code still exists. Measure the voltage of the throttle sensor. All three wires are 5V to the ground, and there is no voltage between the three wires. Intake air temperature and pressure sensor to ground SV. According to the correct data, the 1 pin of the throttle position sensor is 5V, but it is a signal in February and ground in March. However, the measured voltage is inconsistent with the data, and it is suspected that the grounding contact of the line is poor. It may be that the grounding wire was not connected properly when repairing the transmission. One by one, it was found that the ground wire on the rear blade plate of the left headlight was not well connected. After treatment, the fault disappeared and was delivered to the customer.

The next day, the customer reported the same failure. When reading the data stream, it is found that the intake air temperature is -32℃, the coolant temperature is the same, and the throttle opening is 13.2. Looking at the circuit diagram, it is found that three sensors use a ground wire. On the 30th pin of the ECU, * * * uses the 5V power supply on the 12 pin of the ECU, and outputs it after the ECU is powered on. Because the sensor plug has 5V to the ground power supply, it means that the ECU outputs 5V and judges that the sensor ground wire is open. The 30 feet of the sensor ECU are blocked, but the vehicle can hit it, indicating that the ECU is not a big problem, and the only doubt is the wiring. Because there are too few Huapu cars, the wiring harness is not easy to buy, so the wiring harness is removed for inspection, and it is found that there is "copper rust" on the 30 feet of ECU, and the wiring harness is easily broken. Handle it properly. Feet, delivered to the owner, the problem no longer appears.