General Information

Component Location





General Description

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 condenser and once hazardous gas is detected, it delivers the voltage signal to ECU for closing intake door.

DTC Description

The ECM sets DTC B1257 if there is an open circuit in AQS sensor signal harness or the measured voltage value of the sensor is more than the threshold value.

DTC Detecting Condition





Schematic Diagram





Signal Waveform

** Voltage value of AQS sensor as a function of position of operating condition.