Circuit Description
The Passenger sun load sensor is a light sensitive photodiode that controls signal voltage to the HVAC Control Module (HCM). This photodiode is different from standard thermistor sensors and resistance measurements will not produce accurate results. The HCM monitors voltage on circuit 1548 to the sensor. When the sensor is in direct sun light the HCM reads a low signal voltage at terminal B3, connector C2. When the sensor is shaded, the signal voltage increases. Signal voltage will vary from 5 V (open circuit) to 0 V (short circuit).
Conditions for Setting the DTC
| • | The ignition is ON. |
| • | Circuit shorted or open. |
Action Taken When the DTC Sets
| • | A default value of dark or no sun load will be used by the HCM. |
| • | The default value will allow the system to operate. |
Conditions for Clearing the DTC
| • | Using a Scan Tool . |
| • | A history DTC will clear after 50 fault free ignition cycles. |
| • | HCM battery voltage is interrupted. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Perform the Body Control Module (BCM) diagnostic system check before continuing with the diagnosis of this DTC.
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Determines whether the sensor is operational.
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Determines that the DTC was not set in error.
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Determines if the malfunction is the sensor or an open or a short in a circuit.
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Determines if the HCM or an open or short is causing the malfunction.
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The Scan Tool checks for proper sensor operation. Clear all the DTC's after the repair procedures are complete.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the BCM diagnostic system check performed? | -- | Go to Step 2 | ||
Did the sensor counts increase from the noted value? | -- | Go to Step 3 | Go to Step 4 | |
Did the DTC reset? | -- | Go to Step 4 | ||
Refer to Measuring Voltage in Wiring Systems. Is the voltage within the specified value? | 4.5-5.5 V | Go to Step 8 | Go to Step 5 | |
5 | Measure the voltage between the sun load sensor harness connector terminal A and ground. Refer to Measuring Voltage in Wiring Systems. Is the voltage within the specified value? | 4.5-5.5 V | Go to Step 9 | Go to Step 6 |
6 | Measure the voltage between the HCM terminal B3 and ground. Refer to Measuring Voltage in Wiring Systems. Is the voltage within the specified value? | 4.5-5.5 V | Go to Step 7 | Go to Step 10 |
7 | Repair an open or short in CKT 1548 (GRY). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 12 | -- |
8 | Replace the passenger sun load sensor. Refer to Sun Load Sensor Replacement Is the repair complete? | -- | Go to Step 12 | -- |
Are all of the HVAC sensor DTCs present? | -- | Go to Step 10 | Go to Step 11 | |
10 |
Is the repair complete? | -- | Go to Step 12 | -- |
11 | Repair an open or short in CKT 61 (YEL). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 12 | -- |
Is the system operating correctly? | -- | -- |
