I have an S500, and in this case the computer modules are limited to 55ºC.
If the temperature rises above this value the car goes into "limp mode".
There is a ventilator in the modules compartment that assures the temperature remains below 55ºC in all conditions.
Check if your model has this vent. It could be it.

I hope it can help...

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Folgado
S 500