Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B0509 02: Outside Air Temperature Sensor 3 Circuit Short to GroundDTC B0509 05: Outside Air Temperature Sensor 3 Circuit Short to Battery or Open
DTC B0514 02: Output Air Temperature Sensor 4 Circuit Short to Ground
DTC B0514 05: Output Air Temperature Sensor 4 Circuit Short to Battery or Open
DTC B3578 02: Output Air Temperature Sensor 6 Circuit Short to Ground
DTC B3578 05: Output Air Temperature Sensor 6 Circuit Short to Battery or Open
DTC B3583 02: Output Air Temperature Sensor 7 Circuit Short to Ground
DTC B3583 05: Output Air Temperature Sensor 7 Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Upper Left Air Temperature Sensor Signal | B3578 02 | B3578 05 | B3578 05 | -- |
Upper Right Air Temperature Sensor Signal | B0509 02 | B0509 05 | B0509 05 | -- |
Lower Left Air Temperature Sensor Signal | B3583 02 | B3583 05 | B3583 05 | -- |
Lower Right Air Temperature Sensor Signal | B0514 02 | B0514 05 | B0514 05 | -- |
Circuit Description
Air temperature sensors allow the HVAC control module to monitor the temperature of the discharge air in the HVAC ducts. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. When the duct air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the duct air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where 1 volt is approximately equal to 51 counts.
| • | DTC B0509 is for the Right Upper Air Temperature Sensor |
| • | DTC B0514 is for the Right Lower Air Temperature Sensor |
| • | DTC B3578 is for the Auxiliary Upper Air Temperature Sensor |
| • | DTC B3583 is for the Auxiliary Lower Air Temperature Sensor |
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
| • | The HVAC control module detects the sensor signal circuit is less than 0.1 volt or 5 counts. |
| • | The HVAC control module detects the sensor signal circuit is more than 4.9 volts or 250 counts. |
Action Taken When the DTC Sets
The HVAC control module uses a default air temperature value for further automatic control calculations. The default values are not displayed on the scan tool.
Conditions for Clearing the DTC
| • | The DTC will become history if the HVAC control module no longer detects a failure. |
| • | The history DTC will clear after 100 fault-free ignition cycles. |
| • | The DTC can be cleared with a scan tool. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the appropriate duct temp sensor harness connector at the appropriate duct temp sensor.
- Test for less than 1.0 ohm of resistance between the low reference circuit terminal 2 and ground.
- Ignition ON, verify the appropriate Duct Temp Sensor Voltage parameter is greater than 4.9 volts or 250 counts.
- Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Duct Temp Voltage parameter is less than 0.1 volt or 5 counts.
- If all circuits test normal, replace the appropriate duct temp sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for HVAC control module replacement, setup, and programming |
