You don't get it.
ECM = Engine Control Module
TCM = Transmission Control Module
ECM-530D (P0700) is stored in the ECM when the TCM requests that the ECM light up the malfunction indicator lamp (MIL).
If you erase ECM-530D (P0700) it will come back unless the TCM sends another request.
Unless you have a scanner that can read and reset the TCM codes, the error codes that resulted in the original requests that caused the now erased ECM-530D (P0700) may still be in the TCM.
When a control module has an error code, it sometimes use a substitute value that keep you going but can result in degraded performance. This might be the source of your "sluggish" performance.
That is why I said you need a scanner that can read and erase codes stored in the TCM.
In short: ECM-530D (P0700) means that the ECM got a message from the TCM that there is a problem in the transmission. No details, you need to contact the TCM to find out what the complaint is.