DTC U1073: Control Module Communication Bus "SONAR-CAN" OFF

WARNING: This page is about a different variant/trim than selected.

DTC detecting condition:

RAB control module communication is shut down because of high speed CAN error.

Trouble symptom:

CAN communication is not normal.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>GENERAL DESCRIPTION>CAUTION .

CHECK CAN COMMUNICATION HARNESS.
Perform the basic diagnostic procedure to check for fault in CAN communication harness. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>BASIC DIAGNOSTIC PROCEDURE .

Was the basic diagnostic procedure performed up to step 7?

Yes: Go to 2.

No: Perform the basic diagnostic procedure. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>BASIC DIAGNOSTIC PROCEDURE .
CHECK DTC.
1. Start the engine.
2. Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .
Is DTC U1073 displayed? (Current malfunction)

Yes: Go to 3.

No: It may be a temporary poor contact. Perform the clear memory.
CHECK CAN COMMUNICATION CIRCUIT.
Check CAN communication circuit. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>CAN COMMUNICATION CIRCUIT CHECK>PROCEDURE .

Is CAN communication circuit faulty?

Yes: Repair the faulty portion, following the diagnosis procedure.

No: Go to 4.
CHECK DTC.
1. Perform the inspection using the DTC check sheet. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST>CHECK USING THE DTC CHECK SHEET .
2. Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .
Is DTC U1073 displayed? (Current malfunction)

Yes: Go to 5.

No: System is normal.
CHECK CONTROL MODULE.
1. Turn the ignition switch to OFF.
2. Disconnect control modules other than the central gateway control module in order.
  NOTE: When disconnecting ECM, Hybrid vehicle control ECU assembly or VDC control module & H/U, connect resistance of 120 Ω between CAN Hi and CAN Lo as an alternative of end resistance.
3. Turn the ignition switch to ON.
4. Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .
Is there any control module that U1073 is not detected as a current malfunction?

Yes: Replace the control module.

No: Repeat step 5 until U1073 is not detected.