No crank after washing the engine and code U0100

2014 PORSCHE CAYENNE
60,000 MILES • 3.6L • V6 • 4WD • AUTOMATIC
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OMATSOLA BROWN
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I washed the engine and the engine started but after I stopped the engine it wouldn't start. I diagnosed the car and it came up with a U0100 code with no crank. I took out my friend's ECM and engine cranks with no start. apparently because I needed to program the foreign ECM. what could be wrong with my ECM?
May 6, 2020 at 4:11 AM
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KASEKENNY
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So just to make sure we are on the same page. With your ECM in the vehicle it does not crank. With your friends ECM in the vehicle, it cranks but does not start and you have the U0100?

If this is the case then yes, your ECM has a short on the circuit board. More then likely it is a coincidence but could be related to you washing the engine. Clearly the connectors for the ECM are weather resistant but if sprayed directly with water, the water can wick inside the connectors.

I would look for water marks on the connectors and ECM where they mate and if you find any then that was the issue.

However, you are correct that it would not start with the other ECM in it because it must be programmed to the vehicle. I have attached that process. Let me know if you have questions. Thanks
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May 6, 2020 at 3:07 PM
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OMATSOLA BROWN
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Thank you for your prompt response. I also noticed that on the floor panel to the right side of the vehicle, under the carpet was full of water and I wonder if this could be a contributory factor to the failure of the dme?
May 7, 2020 at 1:34 AM
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KASEKENNY
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It could. It is hard to say with these types of things what actually caused it. When you say you washed the engine I assume you took a hose and soaked down the engine compartment?

If so, here is a video that does a pretty good job on how to clean the engine bay:

https://youtu.be/PRSoRkM8GcM
May 7, 2020 at 6:49 PM