I'm just about to start putting bits together back onto the S5 TII I bought, and am noticing that the CEL isn't coming on at all when the ignition is turned to on. Was just wondering if there's a very quick way without the engine having to start of testing the ECU (maybe with a multimeter) to see if it's working. Might just be the grounding, but it seems to be grounded pretty well to the rotor housing.

Thanks for any thoughts on this