Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b1571 reference code incompatibility (immobilizer cm to ecm)

Subaru Legacy BN/BS (2015-2019) Service Manual / Keyless access with push button start system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b1571 reference code incompatibility (immobilizer cm to ecm)

DTC DETECTING CONDITION:

Incompatibility of reference code between keyless access CM (model without ID code box) or ID code box (model with ID code box) and ECM occurs.

TROUBLE SYMPTOM:

Engine will not start.

CAUTION:

For replacement procedure of keyless access CM, ECM and ID code box, refer to “REGISTRATION MANUAL FOR IMMOBILIZER” provided as a separate volume.

STEP	CHECK	YES	NO
1.CHECK ECM. Perform ECM registration. Refer to the “REGISTRATION MANUAL FOR IMMOBILIZER” provided as a separate volume.	Is ECM registration finished- And does the engine start-	ECM registration was not performed properly.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1571 REFERENCE CODE INCOMPATIBILITY (IMMOBILIZER CM TO ECM)
2.REPLACE ECM. 1) Install the ECM from other normal operating vehicle (with push button start) which use same ECM to the vehicle to be diagnosed. 2) Perform ECM registration. Refer to the “REGISTRATION MANUAL FOR IMMOBILIZER” provided as a separate volume.	Is ECM registration finished- And does the engine start-	Replace the ECM. Engine Control Module (ECM) > REMOVAL Engine Control Module (ECM) > REMOVAL Install the ECM from other vehicle to the original vehicle.	Replace Keyless access CM (model without ID code box), Keyless Access CM or replace ID code box (model with ID code box). ID Code Box > NOTE

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Other materials:

Inspection
1. Start and warm up the engine.2. Depress the brake pedal, and shift the select lever to “D” range.3. Shift the select lever to “P” or “N” range.4. Depress the brake pedal and hold it.5. Check “secondary pressure sensor voltage” by using Subaru Select ...