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bmw fuel level gauge not working
There are several possible reasons for the inaccurate fuel level display: failure of the left and right fuel level sensors; failure of the wire plug of the sensor connected to the vehicle connection module; failure of the combination instrument; failure of the control unit; software error.
Check the fuel level sensor fault code as follows: Perform the inspection steps. The KOMBI function test of the instrument is normal, and the left and right fuel levels are read as 27L.And 23L, basically normal. Checking the gauge KOMBI data stream can show the correct fuel level left and right, but checking the fuel level on the gauge on the vehicle.
Can not be displayed. Measure the resistance of the left and right fuel level sensors to 85 and 105 ohms respectively, which is normal. The connection between the measuring sensor and the JBE wire is normal, and the wire resistance a value of about 0.3 is normal. Reading the JBE data stream, it is found that the resistance values of the left and right sensors show that the resistance value of more than 6000 ohms is abnormal, which is also inconsistent with the actual measurement at the sensor end.
Check the following for the fault of the air conditioner pressure sensor: JBE supplies 5V to the sensor normally; the signal voltage is 5V; the grounding line voltage is about 10V.
Not normal; pick out the pin of the ground wire to make a ground signal for it, and the air conditioning refrigeration function returns to normal.
Combined with the analysis of the above measurement data results: determine that the JBE is damaged, after replacing the JBE, the functions return to normal, delete the fault code, and hand over the vehicle to the vehicle host. However, after using the car for more than half a month, the owner reported that the fault reappeared, and it was determined that the fault phenomenon was the same as last time, and the fault code was the same.
After inspection, it was determined that the JBE of the car was damaged again. Perform fault analysis again: JBE burns out again, indicating that there is a short circuit in the relevant line. The dry is to disassemble the fuel level sensor on the right side, and a broken wire harness is found. After careful inspection, it is found that the damaged part of the assembled wire harness touches the power supply end of the oil pump. The root cause of the car failure was finally found. At this time, I understood why the JBE always burned out. After replacing the JBE and the fuel level sensor again, the fault did not appear again.
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