Test A

PINPOINT TEST A: DTC B1251 OR DTC B1253 - A/C IN-VEHICLE TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND

Test A1:

Test A1-A3:

Test A3-A5:

Test A5-A6:

Normal Operation
Under normal operation, the in-vehicle air temperature sensor receives a ground from the electronic automatic temperature control (EATC) module through circuit 470 (PK/BK). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the EATC module through circuit 790 (WH/OG).

Possible Causes
- An open in circuit 470 (PK/BK) or 790 (WH/OG).
- A short to voltage in circuit 470 (PK/BK).
- A short to ground in circuit 790 (WH/OG).
- In-vehicle air temperature sensor.
- EATC module.