Hi readers.. Yesterday I fitted the arrow decat. been riding around on it fine. For £180 for the part and a bit of time I've definitely got better mid-range pull and sounds much better. I removed the flapper valve cables and left the actuator in situ. Because of this I didn't get any engine warning errors or so I thought. After doing about 50 miles this afternoon I hit a speed bump quite hard and immediately afterwards i noticed the engine light had come on. Now i don't know if the problem is due to what I've changed or something else. the bike actually rides perfectly ok. How does one find out what is the cause of an engine warning light? Are there any diagnostic tools/adapters etc to read from the engine management system? Help greatly appreciated!!