Test F

PINPOINT TEST F: DTC B1255 OR DTC B1257 - A/C AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND

Test F1-F2:

Test F3-F4:

Test F5-F6:

Normal Operation
Under normal operation, the ambient air temperature sensor receives a ground from the Dual Automatic Temperature Control (DATC) module through circuit 9-FA49 (BN/WH). A 5-volt reference voltage is supplied to the ambient air temperature sensor from the DATC module through circuit 8-FA49 (WH/VT).

Possible Causes
- An open in circuit 9-FA49 (BN/WH) or 8-FA49 (WH/VT).
- A short to together in circuits 9-FA49 (BN/WH) and 8-FA49 (WH/VT).
- A short to ground in circuit 8-FA49 (WH/VT).
- Ambient air temperature sensor.
- DATC module.