Intake pressure sensor

The intake absolute pressure sensor is installed on the intake manifold, and the function diagram reflects the absolute pressure of the intake manifold. When the engine load changes, the pressure of the intake manifold changes, thus changing the resistance of the absolute pressure sensor, thus changing the voltage signal input to the engine controller. The voltage input of the engine controller is related to the atmospheric pressure when the engine is started and the load when the engine is running. The engine controller uses this input signal and the input signals of other sensors to adjust the air-fuel ratio. The failure of the sensor will lead to: the engine cannot be started; Engine acceleration is not smooth; Engine idling is unstable; The engine stalled intermittently. Check: Test the voltage value of terminal 6 of ECU harness with multimeter voltage range. When the ignition switch is turned on, the voltage should be 5V±0.5V；; ; Then use a multimeter to test the voltage value of the sensor terminal C, which should also be 5V±0.5v If it is not, the sensor power cord is broken or the connector is in poor contact.

B, detecting the sensor and outputting a voltage signal value.

Test the output voltage of sensor terminal B with the voltage range of multimeter. When the ignition switch is turned on and the engine is not started, the output voltage of the sensor should be 4-5V; When the engine is idling in engine neutral, the output voltage should be reduced to 1.5-2. 1 volt. At this time, if it is tested from the terminal 1 on the harness side of ECU, its voltage value should also be the above value; If not, the sensor signal connection is open or the connector is in poor contact.

C. test the grounding of the sensor.

Use multimeter Ω to measure the ground resistance of sensor terminal A.. If the resistance value is not zero or large, the ECU connector is mostly disconnected or poorly connected, and the wiring harness should be repaired or replaced.

D, test the grounding condition of the sensor grounding wire of ECU.

Use multimeter Ω to test the resistance between ECU sensor ground wire (terminal 4) and ECU power ground wire (terminal 1 1 or 12), and between ECU power ground wire (terminal 1 1 2) and engine ground wire post (engine ground wire). If the resistance between them is 0 Ω or; 1Ω or more, the sensor grounding wire is poorly grounded, and the reason should be found out and eliminated. If the ground wire of ECU sensor is disconnected from the ground wire of ECU power supply, and the reason cannot be found, the ECU should be replaced.

Many intake manifold absolute pressure sensors output voltage signals converted from atmospheric pressure, which can be checked by turning on the ignition switch. (This method can only prove that the sensor can still work. If the output accuracy drops, this method can't be detected. When checking the output voltage signal of the intake manifold absolute pressure sensor, there should be a certain degree of vacuum in the sensor. In most cases, it can be judged by detecting its output signal every 10 kPa.