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

DTC detecting condition: 

When the ignition switch status of LIN communication and direct line do not match 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  .
   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 (Power Supply)]. 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 & 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 .

   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 (Power Supply)] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2271 displayed? (Current code)

   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 .