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: 

Air conditioning system Ref. to WIRING SYSTEM>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC. 

   Read the DTC relating the meter using the Subaru Select Monitor. Ref. to COMBINATION METER (DIAGNOSTICS)>Read Diagnostic Trouble Code (DTC) .

   Is DTC B1507 displayed? (Current malfunction)

   Yes

   Go to  2 .

   No

   Go to  6 .

2. CHECK CURRENT DATA. 

   Using the Subaru Select Monitor, display «Ambient air temperature» from «Data monitor». Ref. to COMBINATION METER (DIAGNOSTICS)>Read Current Data .

   Is data displayed?

   Yes

   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.

   No

   Go to  3 .

3. CHECK HARNESS (OPEN CIRCUIT). 
   1. Turn the ignition switch to OFF.
   2. Disconnect the meter connector and ambient sensor connector.
   3. 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?

   Yes

   Go to  4 .

   No

   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?

   Yes

   Repair the short circuit of harness or replace harness.

   No

   Go to  5 .

5. CHECK AMBIENT SENSOR. 

   Perform the inspection of ambient sensor unit. Ref. to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>AMBIENT SENSOR .

   Is the check result OK?

   Yes

   Go to  6 .

   No

   Replace the sensor. Ref. to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>AMBIENT SENSOR .

6. CHECK CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect connectors.

   Is there poor contact of connector?

   Yes

   Repair or replace the poor contact of 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.