P1684. The battery has been disconnected within the last 50 starts.
P1391. Intermittent loss of CMP or CKP. CMP is camshaft position sensor. CKP is crankshaft position sensor.
P700.?? A number 1 after a P indicates a manufacturer specific code. A zero (0) after a P indicates a generic code. I take it then that you mean P0700 as I know of no P700 or P1700. A P0700 indicates a transmission control system malfunction.