I assume he cleared the code. If not, I would have it cleared and then drive it far enough, or let it sit running long enough to get the engine easily to operating temperature and to the point the thermostat should have opened and closed a few times. Then check to see if the code is back. I can't recall for sure but it seems like a bad temperature sensor will cause a code, if it does I don't remember how it reads. Either way, as upallnight posts, you should get it fixed right away if the temp is not normal, measured other than by the dash needle.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas