How do you reset ecm on 93 silverado?

To reset the ECM (Engine Control Module) on a 1993 Chevrolet Silverado, you can disconnect the negative battery cable and leave it off for about 15-30 minutes. This will clear the stored trouble codes and reset the ECM. After that, reconnect the battery cable, start the engine, and allow it to idle for a few minutes to let the ECM recalibrate. If needed, you can also use an OBD-I scanner to clear codes.