Except For C5 Model

DTC detecting condition: 

Communication error between the keyless access control module and the hybrid vehicle control ECU assembly.

Trouble symptom: 

READY ON is not possible.

Wiring diagram: 

• Keyless access with push button start system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM .
• Hybrid system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>HYBRID ELECTRIC VEHICLE SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK GROUNDING POINT  .

   Check the ground point of chassis ground.

   Is there any looseness? Are there any foreign matters caught on the ground or contact surface? Are there any oil-soiled areas?

   Yes:  Remove the foreign matters, and tighten to the specified torque. Then start the hybrid system, and check that the fault was removed. Check the DTC, and when DTC B157287 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 [Data Monitor] of [Keyless Access with Push Button Start]. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DATA MONITOR .
   3. Display the following data: [Immobilizer] [Engine start] [Unlock confirmation].

   Data 

   Immobilizer = Unset

   Engine start = E/G Start Permission

   Unlock confirmation = Confirmed

   Is the data displayed as described above?

   Yes:  Go to  3.

   No:  Perform diagnostics with phenomenon. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON .

3. CHECK DATA MONITOR  .

   Use the Subaru Select Monitor to check the following items in [Data Monitor] of [Keyless Access with Push Button Start] when holding down the push button ignition switch while depressing on the brake pedal. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (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 switch to OFF. 

   Is the data displayed as described above?

   Yes:  Go to  4.

   No:  Repair or replace the harness between the keyless access control module and hybrid vehicle control ECU assembly.

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

      Connector & terminal 

      (i241) No. 15 - (i369) No. 12:

   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 

   (i241) No. 17 - Chassis ground:

   (i75) No. 20 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  6.

   No:  Repair or replace the open circuit of harness.

6. CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY  .
   1. Take out the hybrid vehicle control ECU assembly from other normal operating vehicle (with push button start) which use the same hybrid vehicle control ECU assembly, and install it to the vehicle to be diagnosed.
   2. Perform hybrid vehicle control ECU assembly registration. Refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

   Is hybrid vehicle control ECU assembly registration finished? And does the hybrid system start?

   Yes:  Replace the hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE . Install the hybrid vehicle control ECU assembly from other vehicle to the original vehicle.

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