Climate Control Exhaust Gas Sensor: Service and Repair

Air Quality Sensor

• Air Quality Sensor (G238) is installed only on vehicles with a "Comfort" version A/C system.

• Air Quality Sensor (G238) is a highly sensitive electronic component that can be damaged if it comes in direct contact with solvents, fuels or chemicals (e.g. impurities may enter through area - A -).





• Therefore do not install Air Quality Sensors (G238) that were previously stored e.g. in tool boxes.

• Do not store a removed Air Quality Sensor (G238) in areas that are contaminated with solvents, fuels and certain other chemicals (fluids or gases).

• There are different versions of the air quality sensor (G238), each with different functions. Make sure the allocation is correct.

Removing

- Remove the plenum chamber cover.

CAUTION!
Even when the engine is cold, both pump/valve unit valves can be hot.

- If necessary, remove the dome brace (not necessary for all vehicles, various designs).

- Rotate the Air Quality Sensor (G238) 90° and pull sensor - B - upward out of mount.





- Disconnect connectors - A - from Air Quality Sensor (G238).

Terminal assignment in connector - A -

1 B+ (terminal "15")
2 Ground (terminal "31")
3 Signal wire to the Climatronic Control Module (J255) A/C control head.

• The recheck signal emitted by the Air Quality Sensor (G238) cannot be evaluated by workshop equipment. The measured value is displayed in measured value block of the Climatronic Control Module (J255) A/C control head => Vehicle Diagnosis, Testing and Information System VAS 5051.