What do all these codes together mean?

[FAKEREX]

P1718-
AT CAN communication circuit
CAN communication error

U1201-
-CAN-HS counter abnormal
-High speed CAN communication becomes unstable

U1221-
-CAN-HM ECM no-receive data
-Not received error from ECM

PO700-
-Transaxle control system (MIL request)
-Vehicle performance issue

PO0600-
-Serial communication link
-Key on or Engine running; and the PCM detected an unexpected low or high voltage condition on the Serial Communications Link circuit

 

[garry6913]

Break in communication I do believe. Probably a bad ground wire

 

[FAKEREX]

Break in communication I do believe. Probably a bad ground wire

Would that cause the trans to downshift early intermittently? It's done that 2 times in the last 2 days.

 

[garry6913]

Yes cause one of those is a transmission code

 

[FAKEREX]

Yes cause one of those is a transmission code

So the transmission could be ok and it's the "miscommunication" that's causing it to shift weird?

 

[garry6913]

Yes. I have seen more often than not a broken ground wire (if I'm not mistaken there are 2 under the motor one at each head and 2 on the intake). Once again if I remember right Subaru didn't change their engines much and used the 2.5L