DTC B1404: Immobilizer Sub Control Module Communication

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.

Diagnosis start condition:

Battery voltage is 10 V or more.
The remote engine starter was not used to start the engine.

DTC detecting condition:

Other than for C0 model
Communication failure between body integrated unit and central gateway control module
C0 model
Communication failure between immobilizer control module and central gateway control module

Trouble symptom:

Engine will not start.
The security indicator illuminates.

CAUTION:

When the central gateway control module is replaced, registration of the immobilizer system is required. For details, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

CHECK DTC .
1. Turn the ignition switch to ON.
2. Read the DTC of [Body Control] using the Subaru Select Monitor. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)
Is a DTC other than DTC B1404 displayed for [Body Control]? (Current code)

Yes : Perform the diagnosis of DTCs other than B1404.

No : Check the central gateway control module. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE