• | 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 |
---|---|---|---|---|
Air Quality Sensor B+ | 1 | 1 | -- | -- |
Hydrocarbon Sensor Signal | B3843 02 | 1 | 1 | 1 |
NOX Sensor Signal | B2496 02 | 1 | 1 | 1 |
Low Reference | -- | 1 | -- | -- |
Air Quality Sensor Ground | -- | 1 | -- | -- |
1. Exhaust Odor in Vehicle |
The HVAC control module monitors the outside air quality via the air quality sensor assembly while in AUTO mode. The air quality sensor is a 5-wire sensor, 1 ignition voltage circuit, 2 ground circuits and 2 signal circuits. There are 2 sensors inside the air quality sensor assembly. A hydro carbon (HC) sensor which is used for detecting gasoline exhaust fumes and a NOX sensor which is used for detecting oxides of nitrogen. When high levels of hydro carbons (HC) are detected at the front of the vehicle the HC sensor resistance and signal voltage are low. When high levels of NOX are detected at the front of the vehicle the NOX sensor resistance and signal voltage are high.
• | The ignition is ON |
• | DTC B1325 must not be present. |
The HVAC control module detects the air quality sensor signal that is less than 0.09 volt for more than 30 seconds
The driver information center (DIC) will display SERVICE A/C SYSTEM.
• | 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 50 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 greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit test normal test or replace the HVAC control module. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If less than the specified range, test the signal circuit for a open/high resistance. If the circuit tests normal, replace the HVAC control module. |
⇒ | If less than the specified range, test the signal circuit for a 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 |