Except For CO Model

DTC detecting condition: 

Communication error between keyless access control module and ECM

Trouble symptom: 

Engine will not start.

Wiring diagram: 

• Push button start system. Refer to WIRING SYSTEM>PUSH BUTTON START SYSTEM>WIRING DIAGRAM .
• Engine electrical system. Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .
• Engine type: FA

  Courtesy of SUBARU OF AMERICA, INC.

• Engine type: EJ

  Courtesy of SUBARU OF AMERICA, INC.

1. CHECK GROUNDING POINT. 

   Check the grounding point of the engine ground and chassis ground.

   Are there any loose connections, any foreign objects caught in the ground lines or contact surface, or any fluid stains?

   Yes:  Remove the foreign matters, and tighten to the specified torque. Then start the engine, and check that the fault was removed. Check DTC. Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) ., and when DTC B1572 is still displayed. Go to  2.

   No:  Go to  2.

2. CHECK DATA MONITOR. 
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, check the following items on «Data monitor» of «Keyless Access with Push Button Start». Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>DATA MONITOR .

      Data 

      «Immobilizer» = «Unset»:

      «Engine start» = «Engine start permission»:

      «Unlock confirmation» = «Confirmed»:

      Is the data displayed as indicated on the left?

      Yes:  Go to  3.

      No:  Perform diagnostics with phenomenon. Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>ENGINE DOES NOT START .

3. CHECK DATA MONITOR. 

   Using Subaru Select Monitor, check the following items on «Data monitor» of «Keyless Access with Push Button Start», when holding down the push button ignition switch while depressing on the brake pedal (CVT model) or the clutch model (MT model). Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>DATA MONITOR .

   Data 

   «EGI code reception status» = «Reception»:

   NOTE: If «Reception» is displayed, the status changes to «Not yet received» in 10 seconds.

   When performing the check again, perform the check after turning the ignition to OFF.

   Is the data displayed as indicated on the left?

   Yes:  Go to  4.

   No:  Repair or replace the harness between keyless access control module and ECM.

4. CHECK HARNESS (OPEN CIRCUIT). 
   1. Turn the ignition switch to OFF.
   2. Disconnect the keyless access control module connector and ECM connector.
   3. Using a tester, measure the resistance between the keyless access control module connector and ECM connector.

      Connector & terminal 

      Engine type: FA 

      (B574) No. 15 - (E158) No. 43:

      Engine type: EJ 

      (B574) No. 15 - (B135) No. 25:

      Is the resistance less than 10 Ω?

      Yes:  Go to  5.

      No:  Repair or replace the open circuit of harness.

5. CHECK HARNESS (OPEN CIRCUIT). 

   Using a tester, measure the resistance between the keyless access control module connector and chassis ground.

   Connector & terminal 

   (B573) No. 20 - Chassis ground:

   (B574) No. 17 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  6.

   No:  Repair or replace the open circuit of harness.

6. CHECK 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 INSTRUCTIONS FOR IMMOBILIZER" provided as a separate volume.

      Is ECM registration finished? And does the engine start?

      Yes:  Replace the ECM. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>ENGINE control module (ECM) . Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>ENGINE control module (ECM) . Install the ECM from other vehicle to the original vehicle.

      No:  Replace the keyless access control module. Refer to SECURITY AND LOCKS>KEYLESS ACCESS control module .