Pinpoint Test G : B1B71:11 Or B1B71:15: Notes
Refer to Manual Climate Control System , for schematic and connector information.
Refer to Automatic Climate Control System , for schematic and connector information.
Normal Operation and Fault Conditions
The evaporator temperature sensor receives a ground from the HVAC control module. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls the resistance rises. The HVAC control module measures this resistance to determine the temperature at the sensor.
An accurate evaporator temperature is critical to prevent evaporator icing. The HVAC control module uses the temperature measurement to signal the PCM to disengage the A/C compressor before the evaporator temperatures are cold enough to freeze the condensation. This prevents ice blockage of airflow over the evaporator core.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B1B71:11 | Evaporator Temperature Sensor: Circuit Short to Ground | This CMDTC and on demand DTC sets when the HVAC control module senses lower than expected voltage on the sensor feedback circuit, indicating a short to ground. |
| B1B71:15 | Evaporator Temperature Sensor: Circuit Short to Battery or Open | This CMDTC and on demand DTC sets when the HVAC control module senses greater than expected voltage on the sensor feedback circuit, indicating a short to voltage or an open circuit or sensor. |
Possible Sources
- Evaporator temperature sensor
- Wiring, terminals or connectors
- HVAC control module