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.
   3. Disconnect the connector from the warning box.
   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.
   3. Disconnect the connector from the warning box.
   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 again.

   NOTE:

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