Sensor and Control Check
Oxygen Sensor And Oxygen Sensor Control Behind Catalytic Converter, Checking
Test equipment and shop tools
- Fluke 83 (or equivalent)
- VAG1594A
- VAG1598/31
- VAG1788/10
- VAS5051 with VAS5051/1 - or
- VAG1551 with VAG1551/3 A
NOTE:
- Oxygen sensor control behind the catalytic converter is responsible for final control correction. It is the primary sensor and can override the signal from the oxygen sensor control before the catalytic converter..
- It corrects slight changes in the mixture (i.e. enrichment) via the oxygen sensor before catalytic converter by holding the oxygen sensor control before catalytic converter at its higher or lower limit for a specific time (duration). If this time is in the positive range (i.e. 50 ms), mixture is shifted in the -enrich- direction. If this time is in the negative range (i.e. -50 ms), mixture is shifted in the -lean- direction.
Component location of connectors for oxygen sensors 2 behind catalytic converter:
The harness connector for Oxygen sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130 is located beneath the carpet on passenger side.
The harness connector for Oxygen sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131 is located beneath the carpet on driver side.
Test conditions
- Perform road test and do not erase DTC memory.
- Coolant temperature at least 85 °C
- Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAS5051 or VAG1551" under Powertrain Management. Testing and Inspection
When doing this the engine must be at idle.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- to select function "Basic Setting" and confirm entry with -Q- button.
NOTE: During the basic setting the Evaporative Emission (EVAP) canister purge regulator valve -N80 is closed and the A/C compressor is switched off
Indicated on display
Basic Setting
Input display group number XXX
- Press buttons -0-, -3- and -4- to select "display group number 034" and confirm entry with -Q- button.
When indicated on display:
System in Basic Setting 34 ->
1 2 3 4
- Adjust engine speed using
VAG1788/10 to 2800 - 3200 RPM.
- Continue test as soon as display field 2 indicates an exhaust temperature of more than 200 °C.
NOTE: This process can take a few minutes.
- Press -C- button.
- Adjust engine speed using
VAG1788/10 to 1900 - 2400 RPM.
When indicated on display:
Basic Setting Q
Input display group number XXX
- Press buttons -0-, -3- and -0- to select "display group number 030" and press -Q- button to confirm input.
When indicated on display:
System in Basic Setting 30 ->
1 2 3 4
- Check oxygen sensor status for oxygen sensor behind catalytic converter in display field 2.
NOTE: "Oxygen sensor status" indicates status of oxygen sensor control and oxygen sensor.
Display Group 030:
- Press -C- button.
- Increase engine speed until exhaust temperature 250 °C is reached (display group 34, display field 2)
When indicated on display
Basic Setting Q
Input display group number XXX
- Press buttons -0-, -4- and -3- to select "display group number 043" and press -Q- button to confirm input.
When indicated on display
System in Basic Setting 43 ->
1 2 3 4
- Check specified value in display field 4.
Display Group 043:
If the specified value of "B1-S2 OK" is reached:
- Press -C- button.
Display Group 044:
- Press buttons -0-, -4- and -4- to select "display group number 044" and press -Q- button to confirm input.
If the specified value of "B2-S2 OK" is reached:
- Press -C- button.
Checking oxygen sensor control behind catalytic converter
- Carry out road test for approx.: 10 minutes.
Indicated on display
Basic Setting Q
Input display group number XXX
- Press buttons -0-, -3- and -7- to select "display group number 037" and press -Q- button to confirm input.
Indicated on display
System in Basic Setting 37 ->
1 2 3 4
- Check oxygen sensor voltage in display field 2.
Display Group 044:
- Check dwell time (hold up) between oxygen sensor 1 before catalytic converter and oxygen sensor 2 behind catalytic converter in display field 3 and diagnostic result in display field 4.
- Press -C- button.
- Press buttons -0-, -3- and -8- to select "display group number 038" and press -Q- button to confirm input.
Display Group 038:
Indicated on display: (1 - 4 = display fields)
System in Basic Setting 38 ->
1 2 3 4
Evaluation display group 037 and 038
Continuation
If the specified value in display group 037 and 038, display 3 or 4 is not obtained:
- Check exhaust system and catalytic converter for leaks (check clamps and exhaust for damage)
- Replace particular oxygen sensor before catalytic converter.