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.