DTC B2786: Steering Lock Control Module Communication

DTC detecting condition:

When LIN transmission frame is received from steering lock control module once, but cannot be received for 10 seconds in a row during LIN bus Wake-up.

Trouble symptom:

The steering lock cannot be released.

Wiring diagram:

Keyless access with push button start system Ref. to WIRING SYSTEM (CROSSTREK MODEL)>Keyless Access With Push Button Start System>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

For replacement procedure of keyless access control module and steering lock control module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume. For more details contact an Authorized Subaru dealership.
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>General Description>CAUTION .

CHECK DTC .
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) .

DTC Check

Are DTCs other than DTC B2786 displayed? (Current malfunction)

Yes: Perform the diagnosis of DTCs other than B2786. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)>LIST .

No: Go to 2.
CHECK HARNESS (OPEN CIRCUIT) .
1. Disconnect the keyless access control module connector.
2. Disconnect the steering lock control module connector.
3. Using the tester, measure the resistance between terminals.
  Connector & terminal
  
  (i241) No. 20-(i47) No. 5:
Is the resistance less than 1 Ω?

Yes: Go to 3.

No: Repair or replace the open circuit of harness.
CHECK HARNESS (GROUND SHORT CIRCUIT) .
Using a tester, measure the resistance between the keyless access control module and chassis ground.

Connector & terminal

(i241) No. 20-Chassis ground:

Is the resistance 10 kΩ or more?

Yes: Go to 4.

No: Repair or replace the short circuit of the harness.
CHECK HARNESS (OPEN CIRCUIT) .
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 5.

No: Repair or replace the open circuit of harness.
CHECK HARNESS .
1. Turn the ignition switch to ON.
2. Using a tester, measure the voltage between the steering lock control module connector and chassis ground.
  Connector & terminal
  
  (i47) No. 6 (+)-Chassis ground (-):
  
  (i47) No. 7 (+)-Chassis ground (-):
Is the voltage 11-14 V?

Yes: Go to 6.

No: Repair or replace the faulty portion of the power supply circuit.
CHECK STEERING LOCK CONTROL MODULE .
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start]. Ref. to COMMON (diag)>CLEAR MEMORY .
  Clear memory
3. 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) .
  DTC Check
Is DTC B2785 displayed?

Yes: Replace the keyless access control module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE .

No: Go to 7.
CHECK STEERING LOCK CONTROL MODULE .
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start]. Ref. to COMMON (diag)>CLEAR MEMORY .
  Clear memory
3. 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) .
  DTC Check
Is DTC B2786 displayed? (Current malfunction)

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

No: Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.