I have seen, on certain late model Jaguars, where whenever the owner would run the car through the car wash it would go into limp home mode and throw multiple codes. Seems that there are some openings on the cowling at the base of the windshield that if left open will allow water to drain down onto the main connector at the back of the engine. You may have a situation where a connector got wet and now that it has dried out it is fine.

I am going to assume, since they did not get any codes, that the ASR light was not on when they went to read it. Could reinforce the above scenario.

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Jim