DTC B1507: External Air Temperature Open/Short-Circuit Detection

DTC detecting condition:

Open or short circuit in ambient sensor

Trouble symptom:

Defective ambient temperature display
Defective air conditioner operation

Wiring diagram:

NOTE: For the coupling connector, proceed to "WIRING SYSTEM". Air conditioning system Ref. to WIRING DIAGRAM , Air Conditioning System.

Fig 1: External Air Temperature Open/Short-Circuit Detection Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK DTC. Read the DTC relating the meter using the Subaru Select Monitor. Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .	Is DTC B1507 displayed? (Current malfunction)	Go to step 2 .	Go to step 6 .
2 CHECK CURRENT DATA. Using the Subaru Select Monitor, display «Ambient air temperature» from «Data monitor». Ref. to READ CURRENT DATA .	Is data displayed?	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.	Go to step 3 .
3 CHECK HARNESS (OPEN CIRCUIT). Turn the ignition switch to OFF. Disconnect the meter connector and ambient sensor connector. Using the tester, measure the resistance between terminals. Connector & terminal (i10) No. 23 - (B480) No. 2: (i10) No. 24 - (B480) No. 1:	Is the resistance 10 Ω or less?	Go to step 4 .	Repair the open circuit of harness or replace harness.
4 CHECK HARNESS (GROUND SHORT CIRCUIT). Using the tester, measure the resistance between terminals. Connector & terminal (i10) No. 23 - Chassis ground: (i10) No. 24 - Chassis ground:	Is the resistance 10 Ω or less?	Repair the short circuit of harness or replace harness.	Go to step 5 .
5 CHECK AMBIENT SENSOR. Perform the inspection of ambient sensor unit. Ref. to AMBIENT SENSOR .	Is the check result OK?	Go to step 6 .	Replace the sensor. Ref. to AMBIENT SENSOR .
6 CHECK CONNECTOR. Turn the ignition switch to OFF. Disconnect connectors.	Is there poor contact of connector?	Repair or replace the poor contact of connector.	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.