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With Manufacturer's Scan Tool



Heated Oxygen Sensor (HO2S) After Three Way Catalytic Converter (TWC), Checking

Special tools and equipment
- V.A.G 1551 Scan Tool (or VAG 1552 mobile scan tool) with VAG 1551/3 cable
- VAG 1788/10 RPM adjuster

Test condition





- Coolant temperature must be at least 80°C, See Display group 04, display field 3

- Connect V.A.G 1551 scan tool (VAG 1552). Start engine and select Engine Control Module (ECM) using address word 01. Refer to Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting V.A.G 1551 Scan Tool [1][2][3]Connecting VAG 1551 Scan Tool

Indicated on display

Rapid data transfer HELP
Select function XX


- Press buttons -0- and -4- to select "Basic Setting" function 04. Press -Q- button to confirm input.

Heated Oxygen Sensor (HO2S) 2 bank 1 functional test

Indicated on display

Basic Setting
Input display group number XXX


- Press 0, 4 and 3 for function "display group number 43", and then press Q to exit from input mode.

Indicated on display (1 - 4 = display fields).

System in Basic Setting 43 ->
1 2 3 4


- Use VAG 1788/10 RPM adjuster to adjust engine RPM to 1800-2400 RPM:
- Hold RPM constant at 1800-2400 until indication in display field 2 shows
Cat. temperature at least 350 °C
- and in display field 4:
"Test OFF" changes to "Test ON".
- Continue to hold RPM constant until in display field 4 expected value "B1-S2 OK" is indicated.

If indications do not resemble description:
- Test Heated Oxygen Sensor (O2S) and Oxygen Sensor Control after Three Way Catalytic Converter (TWC). With Manufacturer's Scan Tool

Functional Test for Heated Oxygen Sensor (HO2S) 2 Bank 2

Indicated on display

Basic Setting
Input display group number XXX


- Press 0 and 4 for "Display Group Number 44", and then press Q to exit from input mode.

Indicated on display (1 - 4 = display fields)

System in Basic Setting 44 ->
1 2 3 4


- Use VAG 1788/10 RPM adjuster to adjust engine RPM to 1800-2400 RPM:
- Hold RPM constant at 1800-2400 until indication in display field 2 shows
Cat. temperature at least 350 °C

- and in display field 4: "Test OFF" changes to "Test ON".
- Continue to hold RPM constant until in display field 4 expected value "B2-S2 OK" is indicated.

If indications do not resemble description:
- Test Heated Oxygen Sensor (O2S) and Oxygen Sensor Control after Three Way Catalytic Converter (TWC). With Manufacturer's Scan Tool