Originally Posted by MikeR
The quickest test is to take the car out in the morning and accelerate HARD and see if you have full power...
then get the engine warm/hot and try it again. If you loose power under acceleration when hot... it is likely that the IC pump has failed and not keeping the air cool enough.... the ECU will disengage the SC if the IAT's are too high....
This may not be 100% but it a good indicator...
Do what Mike says but also when you get home, open your door and listen while u turn your car off. If your IC is working, you'll hear the sound of a fan turning off. If you don't hear that sound, then its time to replace the IC