Circuit Description
The HVAC control module monitors the ambient light via a sunload sensor. The HVAC control module uses this information to calculate a solar correction that compensates for the effect of the sun on the vehicle inside air temperature. When the sensor is in direct sunlight, the signal voltage is low. When the sensor is shaded, the signal voltage is high.
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
The HVAC control module detects the signal circuit is less than 0.09 V (5 counts) or greater than 4.90 V (250 counts).
Action Taken When the DTC Sets
A default value will be used for the sensor data by the HVAC control module. The sensor reading displayed on the scan tool in the HVAC data list will be this default value.
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 50 fault free ignition cycles. |
| • | The DTC can be cleared with a scan tool. |
Diagnostic Aids
If condition 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.
-
Scan tool uses a default value, this will not give accurate reading of sensor value if open or short to ground.
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Tests for the possibility of a short to another 5 V reference circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
Does the voltage measure near the specified value? | 5 V | Go to Step 3 | Go to Step 4 | |
3 | Measure the voltage from the sunload sensor signal circuit to the low reference circuit of the sunload sensor. Does the voltage measure near the specified value? | 5 V | Go to Step 6 | Go to Step 5 |
4 | Test the sunload sensor signal circuit of the sunload sensor for an open, high resistance, short to ground, or short to voltage. 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 |
5 | 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 |
6 | 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 7 |
7 | Test the sunload sensor resistance. Does the resistance measure within the specified range? | 34k-200k ohms | Go to Step 8 | Go to Step 10 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | |
9 | Inspect for poor connections at the harness connector of the HVAC control module. 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 module. Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
