Circuit Description
The HVAC control processor monitors the ambient light on the inside of the vehicle through a light sensitive sunload sensor. The HVAC control processor uses this information to compensate for the effect of the sun on the inside air temperature of the vehicle. When the sensor is in direct sunlight, the signal voltage is low. When the sensor is covered, the signal voltage is high. The HVAC control processor maintains the selected air temperature by performing the following functions:
| • | Requesting engagement of the A/C compressor clutch |
| • | Controlling the door position of the air temperature actuator |
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
The HVAC control processor detects the signal circuit is less than 5 counts (0.09 volts).
Action Taken When the DTC Sets
A default value will be used for the sensor data by the HVAC control processor. The scan tool displays the default value of the Solar Sensor parameter in the Heating and Air Conditioning data list. The scan tool displays the actual value of the Raw Solar Sensor parameter in the Heating and Air Conditioning Open/Short data list.
Conditions for Clearing the DTC
| • | The DTC will become history if the HVAC control processor no longer detects a condition. |
| • | The history DTC clears after 50 fault-free ignition cycles. |
| • | The DTC can be cleared with a scan tool. |
Diagnostic Aids
If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests for the proper operation of the circuit in the high voltage range.
-
Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: HVAC Schematics | |||
1 | Did you perform the HVAC Diagnostic System Check? | Go to Step 2 | |
2 |
Does the scan tool display Open or Short? | Go to Step 3 | Go to Diagnostic Aids |
Does the scan tool display Open? | Go to Step 5 | Go to Step 4 | |
Does the scan tool display Short? | Go to Step 6 | Go to Step 8 | |
5 | Test the signal circuit of the sunload sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 |
6 | Test the signal circuit of the sunload sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 7 |
7 | Test the low reference circuit of the sunload sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 |
8 | Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
9 | Inspect for poor connections at the harness connector of the HVAC control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
10 | Replace the sunload sensor. Refer to Sun Load Sensor Replacement . Did you complete the replacement? | Go to Step 12 | -- |
11 |
Important: Perform the recalibration procedure for the HVAC control processor. Replace the HVAC control processor. Refer to HVAC Control Processor Replacement . Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
