DTC B2788: IGN Signal Correlation (Steering Lock Control Module)

DTC detecting condition: 

When one second elapses while the ignition switch status is not compatible between LIN communication and direct line.

Trouble symptom: 

The steering lock cannot be released.

Wiring diagram: 

Keyless access with push button start system Ref. to WIRING SYSTEM>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK FUSE  .

   Check the fuse. Ref. to SECURITY AND LOCKS>RELAY AND FUSE>INSPECTION .

   Is the check result OK?

   Yes  : Go to  2 .

   No  : Replace the fuse. When the replaced fuse is blown immediately, check the power supply circuit for short-circuited.

2. CHECK DATA MONITOR  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Keyless Access with Push Button Start]. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DATA MONITOR .
      • IGN1/2 relay monitor (drive output)

   Is the display normal according to the ignition switch operation?

   Yes  : Go to  3 .

   No  : Go to  5 .

3. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the steering lock control module connector.
   3. Using a tester, measure the resistance between the steering lock control module connector and chassis ground.

      Connector and terminal 

      (i47) No. 1 - Chassis ground:

   Is the resistance less than 1 Ω?

   Yes  : Go to  4 .

   No  : Repair or replace the open circuit of harness.

4. CHECK HARNESS  .
   1. Connect the steering lock control module connector.
   2. Using a tester, measure the voltage between the steering lock control module connector terminals.

      Connector and terminal 

      (i47) No. 6 (+) - (i47) No. 1 (-):

   Is the voltage 11 - 14 V with IG ON?

   Is the voltage less than 1 V with IG OFF?

   Yes  : Replace the steering lock control module. Ref. to SECURITY AND LOCKS>STEERING LOCK CONTROL MODULE .

   No  : Check the DC power supply circuit.

5. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Keyless Access with Push Button Start] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2271 displayed? (Current malfunction)

   Yes  : Perform the diagnosis of DTC B2271. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2271: IGN RELAY CONTROL CIRCUIT .

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