Test B: DTC B1255 or DTC B1257 - Ambient Temperature Sensor Open Circuit or Short to Ground

PINPOINT TEST B: DTC B1255 OR DTC B1257 - AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND

B1-B3:

B3-B5:

B5-B7:

Normal Operation
Under normal operation, the ambient air temperature sensor receives a ground from the EATC module through circuit 3051 (BK/YE). A 5-volt reference voltage is supplied to the ambient air temperature sensor from the EATC module through circuit 3060 (GY/RD).

Possible Causes
- An open in circuit 3051 (BK/YE) or 3060 (GY/RD)
- A short to voltage in circuit 3051 (BK/YE)
- A short to ground in circuit 3060 (GY/RD)
- Ambient air temperature sensor
- EATC module