Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

Trouble symptom:

Cannot communicate with [Reverse Automatic Braking].

Detecting condition:

Defective harness connector
Power supply circuit malfunction
Defective RAB Control Module
Defective CAN communication circuit
Defective Subaru Select Monitor

Wiring diagram:

Reverse Automatic Braking system Ref. to WIRING SYSTEM>REVERSE AUTOMATIC BRAKING
CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to REVERSE AUTOMATIC BRAKING (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

CHECK IGNITION SWITCH .
Check the ignition switch.

Is the ignition switch ON?

Yes : Go to 2.

No : Turn the ignition switch to ON, and Go to 2.
CHECK BATTERY .
1. Turn the ignition switch to OFF.
2. Check the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>BATTERY>INSPECTION
Is the check result OK?

Yes : Go to 3.

No : Charge or replace the battery.
CHECK FUSE .
Check the fuse. Ref. to WIRING SYSTEM>REVERSE AUTOMATIC BRAKING

Is the check result OK?

Yes : Go to 4.

No : Replace the fuse. If the replaced fuse has blown out immediately, repair the short circuit to ground in harness between fuse - RAB Control Module.
CHECK LAN SYSTEM .
Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE

Is the check result OK?

Yes : Go to 5.

No : Perform the inspection according to the diagnosis for LAN system.
CHECK RAB CONTROL MODULE CONNECTOR .
1. Turn the ignition switch to OFF.
2. Check RAB Control Module connector.
Is the RAB Control Module connector inserted into the RAB Control Module until the clamp locks?

Yes : Go to 6.

No : Insert the RAB Control Module connector to RAB Control Module.
CHECK POWER SUPPLY CIRCUIT (OPEN) .
1. Disconnect the RAB Control Module connector.
2. Turn the ignition switch to ON.
3. Using a tester, measure the voltage between the RAB Control Module connector and chassis ground.
  Connector & terminal
  
  (L81) No. 1 (+) - Chassis ground (-):
  
  (L81) No. 13 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes : Go to 7.

No : Repair the open circuit in the harness between fuse and RAB Control Module connector.
CHECK GROUND CIRCUIT (OPEN) .
1. Turn the ignition switch to OFF.
2. Using a tester, measure the resistance between the RAB Control Module connector and chassis ground.
  Connector & terminal
  
  (L81) No. 2 - Chassis ground:
Is the resistance less than 1 Ω?

Yes : Go to 8.

No : Repair the open circuit of harness between RAB Control Module connector and chassis ground.
CHECK POOR CONTACT OF CONNECTORS .
Check the RAB Control Module power supply, ground circuit, or data link connector for poor contact.

Is there poor contact of RAB Control Module power supply, ground circuit, and data link connector?

Yes : Repair the poor contact of connector.

No : Replace the RAB Control Module. Ref. to REVERSE AUTOMATIC BRAKING>REVERSE AUTOMATIC BRAKING CONTROL MODULE