For C0 And C5 Models

Diagnosis start condition:

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

DTC detecting condition:

Reference code incompatibility between immobilizer control module and ECM

Trouble symptom:

Engine will not start.
The security indicator illuminates.

CAUTION: When the immobilizer control module is replaced, registration of the immobilizer system is required. For details, (Contact an authorized Subaru Dealership)

Step	Check	Yes	No
1 CONFIRM NUMBER OF REGISTERED IMMOBILIZER KEY. Confirm the number of registered immobilizer key. (Contact an authorized Subaru Dealership)	Is the number of registration 0?	Go to step 2	Go to step 3
2 PERFORM IMMOBILIZER SYSTEM REGISTRATION. Register the immobilizer system. (Contact an authorized Subaru Dealership)	Is registration complete?	Finish the diagnosis.	Go to step 3
3 PERFORM ECM REGISTRATION. Perform ECM registration. (Contact an authorized Subaru Dealership)	Is registration complete?	Finish the diagnosis.	Go to step 4
4 CHECK DTC. Perform the Clear Memory Mode. Ref. to CLEAR MEMORY MODE Read the DTC of the ECM. Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC)	Are DTCs other than DTC B1571 displayed?	Perform the diagnosis of DTCs other than B1571.	Go to step 5 .
5 PERFORM ECM REGISTRATION. Replace the ECM. Ref. to ENGINE CONTROL MODULE (ECM) . Ref. to ENGINE CONTROL MODULE (ECM) Perform ECM registration. (Contact an authorized Subaru Dealership)	Is registration complete?	Finish the diagnosis.	Proceed to "Correspondence table when registration is not possible" (Contact an authorized Subaru Dealership). If the registration still does not work properly, replace the immobilizer control module. Ref. to BODY INTEGRATED UNIT