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Let me get this straight. The ECM prevents engine knock in the GT that is caused by using low grade gas?How do you know if it is working?How do you reset the ECM?What would cause you to need to reset the ECM?

ECM Electronic Control Modulebasicly it controls all the functions of your engine. if its defective most likely your car will run like crap or you will have a CEL code flashing on your dash.orAn acronym for electronic control module. The on-board computer that controls fuel delivery, emissions, and on-board diagnostics, for the vehicle's engine management systems.

As scherry said, it controls and oversees the whole engine. As part of this, it has a knock sensor and will change the timing and thus performance to prevent knocking. Using lower octane gas in the GT makes knocking more likely and would cause the ECM to make adjustments. Despite this, it's still not a good idea to use regular in the GT except when you don't have an alternative.I don't know how to reset it, and you should never need to reset it yourself. The only reason it would be reset normally would be as part of an engine repair.

sometimes the ECM is also referred to as the ECU, for engine control unit, or PCM, for powertrain control module. I guess PCM is more accurate because on cars with auto transmissions, it also has some control of the shift points.In general if the ECM isn't working, the car will either run very poorly or not at all. It gets input from a number of different sensors, so if one of those was sending it bad information, it may cause the car to run incorrectly.Supposedly if you disconnect the battery for some amount of time it will reset the ECM. I don't know how much time, 15 minutes is what some people have said. When people deliberately reset their ECM, it is usually because they have had a check engine light and want to clear the light to see if it wil come back, either to see if the problem causing the CEL was some random thing or maybe a repair was done and they don't want to wait for the ECM to get around to clearing the light on it's own. For example, if you don't tighten the gas cap, vacuum tests on the fuel system will cause a check engine light. The fix is easy, screw the gas cap on tight, but it will take a number of automated test cycles by the ECM to determine that the problem has fixed, depending on how you drive it could take a long time, but if you reset the ECU, the light goes away right away, and if it stays away you know you've fixed the problem.Now, the first question, "The ECM prevents engine knock in the GT that is caused by using low grade gas?" As I understand it, when the knock sensor detects engine knocking, the ECM changes ignition timing to try to eliminate the knock. There is only a finite range of timing adjustment though, and it is possible that the ECM may not be able to completely eiminate the engine knock resulting from using a fuel of lower octane than required Are you asking these questions because you are using low grade gas in a GT and the ECM is not able to adjust the timing enough to completely eliminate engine knock? There is a simple solution for that problem. Don't use low grade gas in your GT. Use 91 or higher octane.