Test B: DTC B1251 Or DTC B1253 - Air Temperature Internal Sensor Circuit Open Or Short To Ground
PINPOINT TEST B: DTC B1251 OR DTC B1253 - AIR TEMPERATURE INTERNAL SENSOR CIRCUIT OPEN OR SHORT TO GROUNDNormal Operation
Under normal operation, the in-vehicle air temperature sensor receives a ground from the HVAC module - electronic automatic temperature control (EATC) through circuit RH104 (BU/BN). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the HVAC module - EATC through circuit VH414 (GN/BU).
- DTC B1251 Air Temperature Internal Sensor Circuit Open - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
- DTC B1253 Air Temperature Internal 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
- In-vehicle air temperature sensor
- HVAC module - EATC
B1-B3:
B3-B5:
