# 2012 X5 35d XDrive - Intermittent Engine Stalls



## bradclanton (Feb 5, 2017)

I have a 2012 X5 35d XDrive with approximately 120k miles. It runs like a top and has for years. But now suddenly the engine will occasionally just stop running. All of the dash lights stay on and I just have to pull over. After a few attempts to start the engine again, it will start right up again and run perfectly until it does it again. There is no consistency to this occurring. It might go two or three days without doing it, then suddenly, boom, it stops running again. I thought at first it might need a new fuel filter or something, but the only code my mechanic can find is a bad glow plug in cylinder 6. He recommended just replacing all 6 glow plugs plus new gaskets since he would already have pulled the intake off. It seems odd to me that a bad glow plug in one cylinder could cause this, particularly when the engine is already warm. But this is a BMW, so anything is possible. I have noticed that I have to pull the key out and put it back in several times to get it to start back up, so I am wondering if there could be something in the ignition system causing this, but wouldn't that throw a code? This is perplexing. Thank you for your input!


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## Milliwatt Rob (Aug 27, 2016)

My guess is an intermittent short in a wiring harness or assembly. Maybe to the start/kill switch?


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## bradclanton (Feb 5, 2017)

Milliwatt Rob said:


> My guess is an intermittent short in a wiring harness or assembly. Maybe to the start/kill switch?


That's a good idea Rob. I wonder if it might be the switch itself? I hate to take it to the dealer. Oh, another mechanic friend of mine ran a different computer and he got a code about the timing. It went away and hasn't shown up other times, but that could be relevant.


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## Milliwatt Rob (Aug 27, 2016)

bradclanton said:


> That's a good idea Rob. I wonder if it might be the switch itself? I hate to take it to the dealer. Oh, another mechanic friend of mine ran a different computer and he got a code about the timing. It went away and hasn't shown up other times, but that could be relevant.


Sure, a failing switch is also a possibility and would be easier to deal with than finding shorts or open circuits in a wiring bundle.


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## Doug Huffman (Apr 25, 2015)

What previous work has been done? A switch failure is unlikely.

35d / M57 glow plugs are strictly necessary only at very low temperatures.

Yes, an electrical fault will most likely cause a BMW hexadecimal Diagnostic Error Code readable only with a BMW aware code reader. BMW DTC allow access to an expert system to cover the “this is a BMW so anything is possible.”. Here is a free excerpt of that expert system.



BMW Fault Code Lookup - BMWFaultCodes



*About*
*BMW Fault Codes Lookup*

This BMW fault code lookup service was created by an enthusiast for enthusiasts.
It is the most comprehensive fault code database available online.
It contains fault codes across all models broken down by ECU variant.

This information is provided solely for informational purposes.
It may not be processed by automatic means of any kind.


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