Test C: DTC B1255 Or DTC B1257 - Ambient Temperature Sensor Open Circuit Or Short To Ground
PINPOINT TEST C: DTC B1255 OR DTC B1257 - AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUNDNormal Operation
Under normal operation, the A/C ambient 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 A/C ambient temperature sensor from the EATC module through circuit 3061 (LB/OG).
- DTC B1255 Ambient Temperature Sensor Open Circuit - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
- DTC B1257 Ambient Temperature Sensor Circuit Short to Ground - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- A/C ambient temperature sensor
- EATC module
C1-C2:
C2-C3:
C4-C5:
