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Hello m5 board my name is Jacob and I own a 2000 m5 I am having some trouble with the ecu I believe.
When ever I drive my car on random occasions it will die under load or right as the load is being taken off the engine!:crying: i don't know where to start diagnosing the problem I have cleaned the terminals to the battery and it still happens.
When ever it does die what happens is all the lights on the cluster will turn off and Gage's will zero out. Where I'm confused is that the radio will stay on as the cluster turns off. I am able to turn the car completely off and restart no problem i am just wondering if anyone has had this problem before or if someone can give me a heads up on how to go about fixing the problem. I am a aircraft mechanic so I will be trying to pinch my penny's and work on it my self any input would be greatly appreciated thanks for your time

Thank you,
Jacob
 

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Do you have any codes stored? Also, it could be a bad DME relay and or more likely faulty ignition switch. Since you say that car dies under load see if you have a faulty crankshaft position sensor.
 

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I had a similar situation where my car would shut off at every stop sign/light. I could keep it alive by keeping the revs above 1k.

I replaced in no particular order:
fuel pump
fuel filter
cleaned out the icv


What finally got it fixed was jumping the fuel pump relay while the car was off. Haven't had the problem since.

Hope this helps/gives you some ideas.
 

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If it was fuel related his cluster wouldn't shut off it would be in position 2 with all the lights on. OP, does your trip odometer go to 0 when this happens?
 

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I agree with rad M5. There has been a rash of ignition switch failures recently and this sounds like another one, with some of the 5 contacts on the switch failing and switching random stuff off. Cycling the switch to restart the car gets it working again.
 

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I would not disagree with the likely culprit being the ignition switch, but there is one thing in the symptoms that could indicate something else. This happens when the alt turns off for only a second or two. If you watch test 9 in the OBC display yoiu will see the voltage drop every time the gas pedal changes significantly.
First thing I would do is check if my battery was good then clean the terminals and check down stream on the two cables where they connect to the car. The ground is easy to follow and the positive goes to a box in the compartment in the rear right of the trunk under the cover.
 
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