Test C: DTC B1255 or DTC B1257 - A/C Ambient Temperature Sensor Open Circuit or Short to Ground
PINPOINT TEST C: DTC B1255 OR DTC B1257 - A/C AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUNDC1-C3:
C3-C5:
C5-C7:
Normal Operation
Under normal operation, the ambient air temperature sensor receives a ground from the electronic automatic temperature control (EATC) module through circuit RH104 (BN/BU). A 5-volt reference voltage is supplied to the ambient air temperature sensor from the EATC module through circuit VH407 (YE/GN).
Possible Causes
- An open in circuit RH104 (BN/BU) or VH407 (YE/GN)
- A short to voltage in circuit RH104 (BN/BU)
- A short to ground in circuit VH407 (YE/GN)
- Ambient air temperature sensor
- EATC module