• | 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 06 | B0158 06 | B0158 07* | B0158 03, B0158 07 |
Inside Air Temperature Sensor Signal | B0163 06 | B0163 06 | B0163 06* | 1 |
Left Sunload Sensor Signal | B0183 06 | B0183 06 | B0183 06* | 1 |
Right Sunload Sensor Signal | B0188 06 | B0188 06 | B0188 06* | 1 |
Evaporator Temperature Sensor Signal | B3933 06 | B3933 06 | B3933 06* | 1 |
Low Reference | -- | B3933 06, B0158 06, B0163 06 | B3933 06, B0158 07, B0163 06 | B0158 07 |
Sunload Sensors Ground | -- | B0183 06, B0188 06 | B0183 06, B0188 06 | -- |
*If the signal circuit is shorted to voltage B0158, B0163, B0183, B0188 and B3933 will all set. 1. Air Temperature Malfunction |
The sunload sensor is a 2-wire photo diode. The vehicle uses left and right sunload sensors. The 2 sensors are integrated into the sunload sensor assembly along with the ambient light sensor. Low reference 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 HVAC control module 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 HVAC control module detects the signal circuit is less than 0.09 volt (5 counts) or more than 4.90 volts (250 counts).
• | The HVAC control module will display dashes for outside air temperature. |
• | The driver information center (DIC) will display SERVICE A/C SYSTEM. |
• | If the DTC is set the system will act as if no sunload condition exists. |
• | The DTC will become history if the HVAC control module no longer detects the condition that set the DTC. |
• | The history DTC will clear after 100 fault-free ignition cycles. |
Automatic HVAC Description and Operation
Control Module References for scan tool information
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If not the specified value, test the appropriate signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the HVAC control module. |
• | Left sunload sensor circuit terminal A |
• | Right sunload sensor circuit terminal B |
• | Left sunload sensor circuit terminal A |
• | Right sunload sensor circuit terminal B |
⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for HVAC control module replacement, setup, and programming |