B1258
DTC B1258 AQS SHORTComponent 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 B1258 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:
Signal Waveform And Data:
Schematic Diagram:
MONITOR DTC STATUS
1. Connect scantool to Data Link Connector (DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor DTC (Diagnostics Trouble Code) on the scantool.
4. Is the same DTC displayed again?
YES - Go to "Inspection/Repair" procedure.
NO - Fault is intermittent caused by poor contact in the sensor's and/or A/C-ECM connector or was repaired and A/C-ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
W/HARNESS INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration,or damage.
3. Has a problem been found?
YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Signal circuit Short Inspection" procedure.
SIGNAL CIRCUIT SHORT INSPECTION
1. Ignition "OFF"
2. A/C-ECU : Connect, AQS sensor : Disconnect.
3. Measure resistance between Signal(+) terminal of AQS sensor harness connector and and chassis ground
Specification : Infinity
4. Is "resistance" display near the specified value?
YES - Go to "Component inspection" procedure.
NO
- Check for short in harness.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
CHECK AQS SENSOR
1. Ignition "OFF"
2. A/C-ECU, AQS sensor : Connect.
3. Ignition "ON"(ENGINE "OFF").
4. Measure voltage between Signal(F/B) terminal of AQS sensor harness connector and and chassis ground. (Component side)
Specification : Refer the specifications in fig.1
5. Is "voltage" display near the specified value?
YES - Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO - Substitute with a known-good AQS sensor and check for proper operation. If the problem is corrected, replace AQS sensor and then go to "Verification of Vehicle Repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verifying that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Using scantool, Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present?
YES - Go to the applicable troubleshooting procedure.
NO - System is performing to specification at this time.