A VOLVO S80L with about Mileage of 6000km. The car at high speed after a period of time, the instrument displays tire pressure monitoring system needs repair.
Fault Diagnosis: This fault is sporadic fault, the vehicle traveling at a low speed, the fault does not appear; after the fault appears, turned off the engine and restarted, the instrument fault messages will disappear automatically; if not turn off, continue driving about 10 min, the instrument fault messages also will automatically disappear.
Use VOLVO VIDA to diagnosis, fault code stored C 1A60 93- rear wheel tire pressure sensor signal failure in the central electronic module. Measuring each wheel tire pressure, were normal; further checks, found the car did not install any accessories, just give glass posted Solar Films.
Use vida dice diagnosis ID number, tire pressure, tire temperature of each tire pressure sensor, are normal; use the remote control to operate the vehicle, function normally, the receiver works well; remove the receiver to check the part number, is 31,407,101, is latest; measuring receiver power, grounding and LIN signals are normal, and the correlation wire connector no loose, each terminal contact is good; upgrade CEM software and factory test to the tire pressure monitoring system, test passed. Start the engine, in information amusement system to complete set tire pressure (MY CAR → Settings → Vehicle Settings → Tire Pressure settings) then road test, driving about 50 km, the fault does not appear.
After 3 days the fault phenomenon and the fault code as before, that means the last repair does not removed. According to related technologies again to maintenance inspection, measurement and setting, and replace the four tire pressure sensors, re-download the TPMS application software, tore the solar film on the glass. Road test about 150 km, the fault does not appear.
After 2 days fault phenomena and fault code as before. Combined with the last maintenance experience, re-sort maintenance ideas, infer the receiver and the rear wheel tire pressure sensor distance is too far, resulting in receiver receives poor rear wheel tire pressure sensor signal. The car receiver mounted behind on the driver information module (DIM), this car has occurred this failure many times, while the other receiver mounted on the roof of the cars has never been the fault.
Troubleshooting: Extend the receiver wire, take the receiver is transferred to the rear of the roof skylight, reset the tire pressure then test the car, the fault does not appears again.
A 2007 Mercedes-Benz S350, powered by Mercedes-Benz M272 engine, mileage 43 000 km. When driving the car or the engine idling sometimes stalled, and after stalled a period of time, the engine can not start.
Maintenance staff connected to the fuel pressure gauge continued to idling observe the vehicle. After about 30min vehicle automatically turn off again, this time fuel pressure gauge measured fuel pressure is about 50kPa, the value show that fuel system pressure is too low, the provisions of the fuel pressure is around 1000kPa. Fuel pressure created by the fuel pump, if the fuel pump does not work, the vehicle fuel system can not be established oil pressure. So maintenance staff check fuel pump related lines, not found signs of damage or corrosion, and then query the circuit diagram by workshop information system, turn on the ignition switch and measure the fuel pump connector 1st terminal (ground terminal) and 3rd terminal (supply-side) between the voltage is 12.2V, standards-compliant, fuel pump relay can be closed normally, it appears that the vehicle has returned to normal at this time.
Maintenance staff through the above diagnostic process analysis, think the direct reason of this failure is fuel pump intermittent not working. May be fuel pump, fuel pump relay intermittent failures, or engine control unit failure. In order to find the point of failure as soon as possible, maintenance staff decided to replace the fuel pump and the fuel pump relay, if after replaced fault cleaned, that means the fault point among the two, otherwise check the engine control unit. After replaced to test, the engine after running 20min at idle speed, again appeared automatic flameout phenomenon, at this time directed at the engine control unit and related lines.
Maintenance staff use Mercedes Star Diagnose connection engine control unit and harness, when the vehicle is turned off failure occurs, measured the voltage between 101 terminal and 113 terminal of diagnosis harness box 050, the result is 0, that mean the circuit have disconnection. In order to find the disconnection point, maintenance staff have also measured the voltage between 101 terminal and 113 terminal and the ground of diagnosis harness box, found the voltage between 113 and the ground is 0, that mean the corresponding engine control unit N3/10 17 terminals and circuit disconnection, through measuring determined the external lines without failure, it can be concluded that the engine control unit internal fault, causing fuel pump relay works abnormal, then leading to the vehicle turn off fault.
After replaced the engine control unit, maintenance staff programmed upgrade the control unit and transport SCN code (control software calibration coding) by mb star c3, finally after repeated test, the fault does not appear.