Communication For Initializing Impossible

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

Detecting condition:

Defective harness connector
Defective central gateway control module

Trouble symptom:

Communication is impossible between central gateway control module and Subaru Select Monitor.
Lost CAN data frequently detected by all units.

Wiring diagram:

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 CENTRAL GATEWAY (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 select the [Central Gateway] using the Subaru Select Monitor.
CHECK BATTERY .
1. Turn the ignition switch to OFF.
2. Measure the battery voltage. Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>BATTERY>INSPECTION
Is the voltage 11 V or more?

Yes : Go to 3.

No : Charge or replace the battery. And then, restart the Subaru Select Monitor.
CHECK BATTERY TERMINAL .
Is there poor contact at battery terminal?

Yes : Replace or tighten the battery terminal.

No : Go to 4.
CHECK FUSE .
1. Remove fuses No. 9, 15 and 38 from main fuse box.
2. Check the fuse. Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM
Is the check result OK?

Yes : Go to 5.

No : Replace the fuse. If the replaced fuse blows out easily, repair the ground short circuit in harness between the central gateway control module and fuse.
CHECK SUBARU SELECT MONITOR COMMUNICATION .
Connect the Subaru Select Monitor to another vehicle to check whether the communication for initializing can be executed normally.

Does the Subaru Select Monitor communicate normally?

Yes : Go to 6.

No : Repair or replace the Subaru Select Monitor.
CHECK INSTALLATION OF CENTRAL GATEWAY CONTROL MODULE .
Turn the ignition switch to OFF.

Is the central gateway control module connector inserted into the central gateway control module until the clamp locks?

Yes : Go to 7.

No : Insert the central gateway control module connector into the central gateway control module.
CHECK CAN COMMUNICATION CIRCUIT .
Check whether or not an inspection of the LAN system CAN communication circuit (DIAG-CAN) was performed.

Was an inspection of the CAN communication circuit (DIAG-CAN) performed?

Yes : Go to 8.

No : Inspect the CAN communication circuit (DIAG-CAN). Ref. to LAN SYSTEM (DIAGNOSTICS)>CAN COMMUNICATION CIRCUIT CHECK>PROCEDURE>DIAG-CAN
CHECK POWER SUPPLY CIRCUIT .
1. Turn the ignition switch to ON. (Engine OFF)
2. Measure the power supply voltage between central gateway control module connector and chassis ground.
  Connector & terminal
  
  (i88) No. 1 (+) - Chassis ground (-):
  
  (i88) No. 2 (+) - Chassis ground (-):
  
  (i88) No. 19 (+) - Chassis ground (-):
Is the voltage 10 - 15 V?

Yes : Go to 9.

No : Repair the open circuit in the harness between the central gateway control module and battery.
CHECK HARNESS CONNECTOR BETWEEN CENTRAL Gateway CONTROL MODULE AND CHASSIS GROUND .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the central gateway control module.
3. Using a tester, measure the resistance of harness between the central gateway control module connector and chassis ground.
  Connector & terminal
  
  (i88) No. 18 - Chassis ground:
  
  (i88) No. 22 - Chassis ground:
Is the resistance less than 10 Ω?

Yes : Go to 10.

No : Repair the open circuit of the central gateway control module ground circuit and poor contact of connector.
CHECK POOR CONTACT OF CONNECTOR .
Is there poor contact of central gateway control module power supply, ground circuit and data link connector?

Yes : Repair the connector.

No : Go to 11.
CHECK SUBARU SELECT MONITOR COMMUNICATION .
1. Turn the ignition switch to ON.
2. Check whether communication to the [Central Gateway] can be executed normally.
Is the [Select Function] screen displayed?

Yes : Check the [Central Gateway] DTC. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)

No : Replace the central gateway control module. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>CENTRAL GATEWAY CONTROL MODULE