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

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

A1-A3:

A3-A5:

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 RH104 (BU/BN). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the EATC module through circuit VH414 (GN/BU).

Possible Causes
- An open in circuit RH104 (BU/BN) or VH414 (GN/BU)
- A short to voltage in circuit RH104 (BU/BN)
- A short to ground in circuit VH414 (GN/BU)
- In-vehicle air temperature sensor
- EATC module