B1251
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PINPOINT TEST 1: DTC B1251 OR B1253 - AIR TEMPERATURE INTERNAL SENSOR CIRCUIT OPEN OR SHORT TO GROUND - HYBRID
Normal Operation
The in-vehicle air temperature sensor receives a ground from the dual automatic temperature control (DATC) module through circuit (GY/L). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the DATC module through circuit (G/L).
- 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.
Possible Causes
- Wiring, terminals or connectors
- In-vehicle air temperature sensor
- DATC module
Diagnostic Procedure
Step 1-Step 4:
