2003 BMW 540i



November, 28, 2009 AT 1:45 PM

Electrical problem
2003 BMW 540i Two Wheel Drive Automatic

My engine check soon and engine failsafe came on. The range has not matched up with how much gas I have in it. Strange little ticks going on. I would start up the car and it would die then I would restart and it would be fine. Before I took it to the mechanics I started it and it just hung there and would not die or turn over. I tried and by the 3rd try it would start. Mechanic diagnosed that I need some new sensors for something then when they put on the sensors the computer they hook up my car to said there was a problem with the throttle body. They took out the sensors put my original sensors back in and put on the the new throttle body. He then told me that they need to " update" the software info for the throttle body. He took it to another mechanic who had the equipment to do this. I was told that I need to " update" everything or just that it hadn't been done for quite some time if ever. My car is now not starting at all. They had to tow it back to my mechanics place where he told me he would have to run a pin test and that he and his friend think there may be rat damage. They had noticed that my low beam had been chewed through by rodent and they suspect all this strange testing run through the diagnostics may be better explained by some unexplained wire damage that should not have otherwise occurred on my 2003 wagon. I just don't know who to believe. I really trust my mechanic, but. My car is not running at all now, where before I brought it at least it was running.


2 Answers


Dr. Hagerty

December, 7, 2009 AT 8:42 AM

Rodent damage can be insidious. When a car that is electrically sophisticated has compromised wiring due to the aforementioned small furry creatures, all bets are off. I also wish to stress that a " regular" (read not BMW trained) may not have the chops to deal with the car. This might be something simple though, have you got spark? Is there fuel pressure? Are the injectors getting a signal? I always like to start with the basics and then go to the complex. A blown fuse might be at the cause of your problem for all I know. The fuses I speak of are in a separate fuse holder and not readily accessible.



December, 7, 2009 AT 10:06 AM

There actually was no rodent damage except to the low beam wire harness. They found corrosion at the the connectors to the ECU. 2 pins affected. 700 dollars later. I alos need to fix my low beam but the BMW dealer says I need to by the whole Low Beam mess at 500.00. The wires were damaged. DOn't really want to pay 500.00. Junk Yard?

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