AQS(Air Quality System) keeps air inside in the most suitable state for driver. In polluted area AQS detects hazardous gas and intercepts inflow automatically, Inversely, In fresh area it allows the inflow of air to prevent the shortage of air and the accumulation of carbon dioxide. AQS sensor is located at front side of condensor and once hazardous gas is detected, it delivers the voltage signal to ECU for closing intake door.
The ECM sets DTC B1258 if there is a short circuit in AQS sensor signal harness or the measured voltage value of the sensor is less than the threshold value.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage check | ● Short circuit in harness ● Faulty AQS sensor ● Fault A/C Control Unit |
Threshold value | ● > 0.1V | |
Detecting time | ● 1sec | |
FAIL SAFE | ● AQS function OFF ● Intake door : return to previous state |
※ Voltage value of AQS sensor as a function of position of operating condition.
Operating condition | Voltage | Note |
Right after IGN "ON" | 2.5V ± 0.3V | preheating(35 ± 2sec) |
normal | 4.3V ± 0.3V | Intake door : REC |
Gas detected | 0.9V ± 0.3V | Intake door : FRE |
