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

DTC detecting condition: 

When mismatch of the ignition switch status of LIN communication and direct line continued for one second.

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  .

   Using the Subaru Select Monitor, check the following items on «Data monitor» of «Keyless Access with Push Button Start». Ref. to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (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. Disconnect the steering lock control module connector.
   2. Using a tester, measure the resistance between the steering lock control module connector and chassis ground.

      Connector & 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 & 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>REMOVAL .

   No: Check the DC power supply circuit.

5. CHECK DTC  .

   Read DTCs of «Keyless Access with Push Button Start» using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (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 SYSTEM (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 .