Operational Readiness of Oxygen Sensor

Operational Readiness of Oxygen Sensor after Catalyst, Checking

Special tools and equipment







- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable

Test conditions
- Coolant temperature must be at least 80 °C, See display group 04, display zone 3.

Functional check
- Connect VAG1551 scan tool (VAG1552). Start engine and select "Address word" 01 of engine control module. Engine must be running at idling speed. (Connecting scan tool and selecting engine control module). Refer to "VAG1551 Scan Tool Tools and Equipment

Indicated on display


Rapid data transfer HELP
Select function XX


- Press keys 0 and 4 for function "Introduction of basic setting" and confirm entry with Q key.

Indicated on display


Basic setting
Input display group number XXX


- Press keys 0, 3 and 6 for "Display group number 36" and confirm entry with Q key.

Indicated on display: (1...4 = Display zones)


System in basic setting 36 ->
1 2 3 4


- Allow engine to run at idle until readout in display zone 2 jumps from "Test OFF" to "Test ON".
- Observe oxygen voltage in display zone 1. The value must rise.
- Allow engine to continue to run at idle until specified value "B1-S2 OK" appears in display zone.

If the specifications are obtained:
- Press -> key.
- Press keys 0 and 6 for function "End output" and confirm entry with Q key.
- Switch ignition off.

If the specifications are not attained:
- Road test vehicle to free oxygen sensor of possible residues and repeat test.

Observe the valid safety precautions when carrying out a road test Technician Safety Information

If the specifications are again not attained:
- Check basic voltage. Refer to "Oxygen Sensor (O2S) Behind Catalytic Converter/Sensor and Sensor Control Check" Testing and Inspection