61-1- Battery voltage malfunction - probably caused by the battery change or a bad battery connection.
86-1- CAN Related failure - Could be virtually any connection that passes data to the ECU
P0420 - Catalyst System Efficiency Below Threshold (Bank 1) - Converter is getting weak, with that mileage it is probably a true code. Could also be a bad O2 sensor, No real way to check that without watching the real data on a scan tool.
The radio not working is likely a security problem. That will probably be a dealer issue as the code needs to be entered and if the battery was disconnected without knowing the security code to re-enter when it powered back on they can retrieve it.
Since the radio is already down, you could try a system reset -
Turn the ignition switch to LOCK (0), 1. And remove the key.
2. Disconnect the negative battery cable first, then positive.
3. Using a jumper wire, short the battery cables together.
4. Turn the ignition switch to ON (II), and wait 10 minutes.
5. Turn the ignition switch to LOCK (0), and remove the key.
6. Remove the jumper wire, and reconnect the positive battery cable first, then negative.
7. Check the applicable service information, and perform the appropriate reset/learn procedures.
8. Enter the anti-theft code, and restore customer settings.
The last step you will not be able to do.
Thursday, March 9th, 2017 AT 3:07 PM