Test B: DTC B1251 or DTC B1253 - A/C In-Car Temperature Sensor Open Circuit or Short to Ground

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

B1-B2:

B3-B5:

B5-B6:

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 together in circuit 470 (PK/BK) and 790 (WH/OG)
- A short to ground in circuit 790 (WH/OG)
- In-vehicle air temperature sensor
- Electronic automatic temperature control (EATC) module