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

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

B1:

B1-B4:

B4-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 3059 (YE/LG). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the EATC module through circuit 3060 (GY/RD).

Possible Causes
- An open in circuit 3059 (YE/LG) or 3060 (GY/RD)
- A short together in circuit 3059 (YE/LG) and 3060 (GY/RD)
- A short to ground in circuit 3060 (GY/RD)
- In-vehicle air temperature sensor
- Electronic automatic temperature control (EATC) module