Test C: DTC B1255 Or DTC B1257 - Air Temperature External Sensor Circuit Open Or Short To Ground
PINPOINT TEST C: DTC B1255 OR DTC B1257 - AIR TEMPERATURE EXTERNAL SENSOR CIRCUIT OPEN OR SHORT TO GROUNDNormal Operation
Under normal operation, the A/C ambient temperature sensor receives a ground from the HVAC module through circuit 3059 (YE/LG). A 5-volt reference voltage is supplied to the A/C ambient temperature sensor from the HVAC module through circuit 3061 (LB/OG).
- DTC B1255 Air Temperature External Sensor Circuit Open - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
- DTC B1257 Air Temperature External 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
- HVAC module
C1:
C1-C3:
C3-C5:
