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• | 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 |
---|---|---|---|---|
Sensor Signal Terminal 3 | B0163 02 | B0163 05 | B0163 05 | 1 |
Sensor Signal Terminal 4 | B0183 02 | B0183 05 | B0183 05 | 1 |
Low Reference | - | B0163 05, B0183 05 | -- | -- |
1. HVAC Malfunction |
The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.
This sensor assembly provides information about:
• | Sun heat intensity |
• | Passenger compartment temperature |
The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0-5 V.
The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.
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.
• | Vehicle in Service Mode. |
• | The HVAC control module is ON. |
The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.
The 5 V identification pulse is not received.
The input signal is static and greater than 4.8 V.
• | The system will use the last valid values as default. |
• | If no value is read at the time of fault, the HVAC control module uses 0 W/m². |
The sensor signal is within specified range between 0.1-4.9 V.
The sensor signal is within specified range between 0.1-4.9 V.
Automatic HVAC Description and Operation
Control Module References for scan tool information
⇒ | If 10 Ω or greater |
2.1. | Vehicle OFF, disconnect the harness connector at the K33 HVAC control module. |
2.2. | Test for less than 2 Ω in the low reference circuit end to end. |
⇒ | If 2 Ω or greater, repair the open/high resistance in the circuit. |
⇒ | If less than 2 Ω, replace the K33 HVAC control module. |
⇓ | If less than 10 Ω |
⇒ | If 2 W/m2 or greater |
4.1. | Vehicle OFF, disconnect the harness connector at the K33 HVAC control module. |
4.2. | Test for infinite resistance between the signal circuit terminal 4 and ground. |
⇒ | If less than infinite resistance, repair the short to ground on the circuit. |
⇒ | If infinite resistance, replace the K33 HVAC control module. |
⇓ | If less than 2 W/m2 |
⇒ | If 20 W/m2 or less |
6.1. | Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode. |
6.2. | Test for less than 1 V between the signal circuit terminal 4 and ground. |
⇒ | If 1 V or greater, repair the short to voltage on the circuit. |
⇓ | If less than 1 V |
6.3. | Vehicle OFF |
6.4. | Test for less than 2 Ω in the signal circuit end to end. |
⇒ | If 2 Ω or greater, repair the open/high resistance in the circuit. |
⇒ | If less than 2 Ω, replace the K33 HVAC control module. |
⇓ | If greater than 20 W/m2 |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for HVAC control module replacement, programming and setup |
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