Not sure by what you mean by "reset". The timing belt is mechanical, if it were installed incorrectly (one tooth off), you would have some valve noise.
The crankshaft timing mark aligned, along with the camshafts timing mark (TDC #1), you then install the belt.
The ECM can be reset by disconnecting the negative battery cable for a minute or two, but if the timing belt was installed incorrectly, it would make no difference.
You would reset the computer if you were installing a new TPS (throttle position sensor). You would do this to reset the TPS voltage at closed throttle value.
Wednesday, January 14th, 2009 AT 6:56 AM