DTC B1502: Warning Box Communication Malfunction

DTC detecting condition: 

Communication error between the combination meter and warning box.

Trouble symptom: 

Improper operation of the warning light in the warning box

Wiring diagram: 

Combination meter system Ref. to WIRING SYSTEM>COMBINATION METER SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POWER SUPPLY CIRCUIT  .

   Turn the ignition switch to ON, and make sure that the combination meter operates properly.

   Is the check result OK?

   Yes:  Go to  2.

   No:  Check the combination meter power supply circuit.

2. CHECK DTC  .

   Read the DTC of [Combination Meter] using the Subaru Select Monitor. Ref. to COMBINATION METER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B1502 displayed? (Current code)

   Yes:  Go to  3.

   No:  Go to  4.

3. CHECK COMMUNICATION CIRCUIT (HARNESS) (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the combination meter. Ref. to INSTRUMENTATION/DRIVER INFO>COMBINATION METER>REMOVAL .
   3. Disconnect the connector from the warning box. Ref. to INSTRUMENTATION/DRIVER INFO>WARNING BOX>REMOVAL .
   4. Using a tester, measure the resistance between the combination meter connector and warning box connector.

      Connector & terminal 

      (i97) No. 12 - (Rf23) No. 2:

   Is the resistance less than 10 Ω?

   Yes:  Replace the warning box. Ref. to INSTRUMENTATION/DRIVER INFO>WARNING BOX .

   No:  Repair the open circuit of harness between combination meter connector and warning box connector.

4. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the combination meter. Ref. to INSTRUMENTATION/DRIVER INFO>COMBINATION METER>REMOVAL .
   3. Disconnect the connector from the warning box. Ref. to INSTRUMENTATION/DRIVER INFO>WARNING BOX>REMOVAL .
   4. Check the connector.

   Is there any fault in the connector?

   Yes:  Repair or replace the connector.

   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.

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