U1300 is indicated when malfunction occurs in communication signal of multi AV system. Indicated simultaneously, without fail, with the malfunction of control units connected to AV control unit with communication line. Determine the possible malfunction cause from the table below.

SELF-DIAGNOSIS RESULTS DISPLAY ITEM
DTC
| Display contents of CONSULTāIII
| Description
| Possible causes/Action to take
|
U1300 U121F
| - AV COMM CIRCUIT [U1300]
- INTERNAL COMM [U121F]
| - Malfunction is detected in AV control unit power supply and ground circuits.
- AV control unit malfunction is detected.
| - AV control unit power supply and ground circuits.
- When there is no malfunction, AV control unit is malfunctioning.
|
U1300 U1240
| - AV COMM CIRCUIT [U1300]
- SWITCH CONN [U1240]
| - Multifunction switch power supply and ground circuits malfunction is detected.
- Malfunction is detected in AV communication circuits between AV control unit and multifunction switch.
- Malfunction is detected in AV communication signal between AV control unit and multifunction switch.
| - Multifunction switch power supply and ground circuits.
- AV communication circuits between AV control unit and multifunction switch.
|