The P1684 code means simply that the battery has been disconnected within the last 50 starts, You can effectively disregard this unless you know that to be false. Then it could be an indication of an impending battery failure.The P0700 code is more troublesome. I collected this information from another source:
What does that mean?
Many vehicles have a control module for the automatic transmission called a transmission control module (TCM). The engine
control module (ECM) communicates with the TCM to monitor the automatic
transmission for faults. If the TCM detects a fault in the automatic
transmission and sets a transmission related fault code, the ECM is
informed of this also and sets a P0700 in the ECM memory.
This illuminates the Malfunction Indicator Lamp
(MIL) to let the driver know there is a problem. If this code is
present and the MIL (Malfunction Indicator Lamp) is illuminated that
basically means there is at least one transmission code set in the TCM's
memory. P0700 is an informational code only. It doesn't point to a
direct fault in the engine, only a general fault in the transmission.
More diagnosis is necessary to identify what the transmission fault is.
This requires a scan tool that will communicate with the transmission
Symptoms of a P0700 DTC may include:
- Malfunction Indicator Lamp (MIL) illumination
- The transmission may exhibit drivability problems like slipping, etc.
More often then not, the cause of this code is that there is a
transmission problem of some kind. The TCM detected the problem and set a
code. P0700 means that a fault code is stored in the TCM. However this
doesn't rule out the possibility of a failed PCM or TCM (unlikely).
For a P0700 the only real solution is to acquire a scan tool that
will communicate with the transmission control module. Extracting this
code from the TCM will be the first step in repairing the fault in the
If the TCM compatible scan tool will not communicate with the
Transmission Control Module then that is a good indication that there
may be a fault with the TCM itself.
Hope this helps!