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　　Engine at various speeds, the oil pressure gauge has no pressure indication.

　　Cause of failure: the power cord of lubricating oil pressure gauge is broken; The electric heating coil in the lubricating oil pressure gauge is burnt out; Lubricating oil pressure sensor is damaged; Engine lubrication system failure.

　　Fault diagnosis: Turn on the ignition switch, remove the lead at one end of the lubricating oil pressure sensor, and conduct an instantaneous grounding test. If the pointer of the lubricating oil pressure gauge moves to the direction of 0. 5 MPa immediately, the lubricating oil pressure gauge is in good condition. At this time, you can remove the sensor and install the removed wire, and use a nail without a pointed end to plug it into the oil hole of the sensor to press the diaphragm. If the lubricating oil pressure gauge moves, it means that the sensor is good and the engine lubrication system is faulty; Otherwise, the sensor is faulty and can be repaired as appropriate. If the lubricating oil pressure gauge still does not move when the wire at one end of the sensor is grounded, one end of the test lamp can be connected to the power terminal of the oil pressure gauge and the other end can be grounded for test. If the test lamp does not light up, the power supply line is disconnected; If the test light is on, it means that the lubricating oil pressure gauge itself or the line to the sensor is faulty. At this point, the grounding test can be conducted at one end of the lead-out terminal of the lubricating oil pressure gauge. If the needle moves normally, it means that the wire from the meter to the sensor is open. Otherwise, the table itself is damaged.

　　2

　　After turning on the ignition switch, the engine has not started, and the pointer of the oil pressure gauge points to the maximum value.

　　Cause of failure: the oil pressure gauge is grounded to the sensor wire; Internal ground of the oil pressure sensor.

　　Fault diagnosis: in this case, turn off the ignition switch immediately to avoid the pressure gauge burning out; During inspection, the wire at one end of the sensor can be removed first, and then the ignition switch can be turned on for test; If the hands don’t move any more, it means that there is a short circuit inside the sensor and it should be replaced or repaired. If the needle still points to the maximum value, check and repair the pressure gauge to the ground of the sensor wire.

　　three

　　When the engine is rotating at various speeds, the pointer of the oil pressure gauge swings randomly and the indication value is not accurate.

　　Cause of failure: the pressure sensitive diaphragm of the oil pressure sensor is deformed due to excessive force; Ablation and oxidation of internal contact surface of oil pressure sensor; Poor contact of connecting wires.

　　Fault diagnosis: Turn on the ignition switch, and check whether the terminals are rusted or loose, and whether the wires are open; If yes, it should be repaired, otherwise, the sensor should be removed and installed on the oil pressure test bench to test the accuracy of its indication. If the difference exceeds 20%, the sensor should be replaced.

　　Jinan Laiwu car keys, online programming, car computer maintenance.