1.CHECK CONNECTOR. 1) Check connecting condition of the A/C CM connector and rear vent actuator connector. 2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC) | | Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1448 REAR VENT DOOR ACTUATOR CIRCUIT OPEN | 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. |
2.CHECK REAR VENT ACTUATOR. 1) Disconnect the rear vent actuator. 2) Short No. 1 and No. 5 of (i177) connector. 3) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC) | | Replace the rear vent actuator. Rear Vent Door Actuator > REMOVAL | Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1448 REAR VENT DOOR ACTUATOR CIRCUIT OPEN |
3.CHECK HARNESS. 1) Restore the temporary shorted lines made in step 2. 2) Turn the ignition switch to ON. 3) Using the tester, measure the voltage between terminals. Connector & terminal (i177) No. 3 (+) — No. 1 (−): | Is the voltage 4.5 — 5.0 V- | Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1448 REAR VENT DOOR ACTUATOR CIRCUIT OPEN | Repair or replace the open circuit of harness. |
4.CHECK HARNESS (OPEN CIRCUIT). Using a tester, check continuity between terminals. Connector & terminal (i177) No. 3 — (i80) No. 12: (i177) No. 1 — (i181) No. 18: (i177) No. 5 — (i80) No. 15: | | Replace the A/C CM. Control Unit > REMOVAL | Repair or replace the open circuit of harness. |