• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Ambient Air Temperature Sensor Signal | B0158 02 | B0158 05 | B0158 05 | 1 |
Upper Air Temperature Sensor Signal | B0173 06 | B0173 05 | B0173 05 | 1 |
Lower Air Temperature Sensor Signal | B0178 06 | B0178 05 | B0178 05 | 1 |
Sunload Sensor Signal | B0183 02 | B0183 05 | B0183 05 | 1 |
Ambient Air Temperature Sensor Low Reference | -- | B0158 05 | -- | -- |
Upper Air Temperature Sensor Low Reference | -- | B0173 05 | -- | -- |
Lower Air Temperature Sensor Low Reference | -- | B0178 05 | -- | -- |
Sunload Sensor Low Reference | -- | B0183 05 | -- | -- |
Sunload Sensor Ground | -- | B0183 05 | -- | -- |
1. Air Temperature Malfunction |
The sunload sensor is a 2-wire photo diode. The vehicle uses a single sunload sensor. The sensor is integrated into the sunload sensor assembly along with the ambient light sensor. Body ground and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor operates within an intensity range between completely dark and very bright. The sensor signal varies between 0-5 volts. The body control module (BCM) converts the signal to a range between 0-255 counts. The sunload sensor provides the HVAC control module with a measurement of the amount of light shining on the vehicle. Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.
Ignition ON.
The BCM detects the signal circuit is less than 0.09 volt (5 counts) or greater than 4.90 volts (250 counts).
The HVAC control module will operate the system as if no sunload condition exists.
• | The DTC will become history if the BCM no longer detects the condition that set the DTC. |
• | The history DTC will clear after 50 fault-free ignition cycles. |
Control Module References for scan tool information
Ignition ON, observe the scan tool Sunload Sensor parameter. The reading should be between 5-250 counts and change with sunlight changes.
Important: If a solar load sensor has an out of range condition caused by a short to voltage, short to ground, or an open/high resistance, the scan tool will display the same value: 225 counts.
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM and HVAC control module replacement, setup, and programming |