Checking ageing of lambda probes before catalytic converter (on vehicles which conform to emission standard EU III) — AUDI
Checking ageing of lambda probes before catalytic converter (on vehicles which conform to emission standard EU III) on Audi: factory workshop procedure.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 12 workshop diagrams for AGB
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
AZB
Test conditions
Coolant temperature at least 85 °C (display group 4, display zone 3)
Test procedure for lambda probe 1 before catalytic converter bank 1
Connect the vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select the engine electronics control unit with "address word" 01 => Page
01-8
.
For this purpose, the engine must be running at idle speed
Rapid data transfer
HELP
Select function XX
When adjacent display appears:
Enter "04" to select "Start basic setting" and confirm with Q key.
Start basic setting
Q
Enter display group number XXX
When adjacent display appears:
Enter "034" for "display group number 034" and confirm entry with Q key.
Test conditions
Engine running at 1900...2200 rpm.
System in basic setting 34
⇒
1
2
3
4
Indicated on display:
Perform the test as soon as "Test ON" appears in display zone 4.
Note:
This process can take a few minutes.
Display zones
1 · 2 · 3 · 4
Display group 034: Diagnosis, lambda probe ageing, (bank 1)
Display · xxxx rpm · xxx °C · x.x s · Test ON
Display · Engine speed · Exhaust gas temperature · Period / Lambda probe before / catalytic converter · Diagnosis status
Range · 0...6800 rpm · 70...850 °C · 0...3.0 seconds · Test OFF / Test ON / B1-P1 OK / B1-P1 NOK
Specification · 1900...2200 rpm · greater than 260 °C · 0.2...2.5 s · B1-P1 OK
Note: · If specification not attained / => ContinuePage 24-99
Note on display zone 2:
Calculated value from engine speed and load.
Note on display zones 3 and 4:
The period specifies the time between two voltage jumps in the lambda probe (e.g. rich - lean - rich) thereby providing a measurement basis for the ageing status of the lambda probe. If the specified time is exceeded, display zone 4 indicates = B1-P1 NOK.
(cont.)
If specification in display zone 4 is not attained:
Replace lambda probe 1 before catalytic converter -G39, bank 1.
Test procedure for lambda probe 1 before catalytic converter, bank 2
Connect the vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select the engine electronics control unit with "address word" 01 => Page
01-8
.
For this purpose, the engine must be running at idle speed
Rapid data transfer
HELP
Select function XX
When adjacent display appears:
Enter "04" to select "Start basic setting" and confirm with Q key.
Basic setting
Q
Enter display group number XXX
When adjacent display appears:
Enter "035" for "display group number 035" and confirm entry with Q key.
Test conditions
Engine running at 1900...2200 rpm.
System in basic setting 35
⇒
1
2
3
4
Indicated on display:
Perform the test as soon as "Test ON" appears in display zone 4.
Note:
This process can take a few minutes.
It is possible that "B2-P1 OK or NOK" will be displayed before "Test ON" appears, since the diagnosis is performed simultaneously with the lambda probe for bank 1. This also applies to further tests.
Display zones
1 · 2 · 3 · 4
Display group 035: Diagnosis, lambda probe ageing, (bank 2)
Display · xxxx rpm · xxx °C · x.x s · Test ON
Display · Engine speed · Exhaust gas temperature · Period / Lambda probe before / catalytic converter · Diagnosis status
Range · 0...6800 rpm · 70...850 °C · 0...3.0 seconds · Test OFF / Test ON / B2-P1 OK / B2-P1 NOK
Specification · 1900...2200 rpm · greater than 260 °C · 0.2...2.5 s · B2-P1 OK
Note: · If specification not attained / => ContinuePage 24-99
Note on display zone 2:
Calculated value from engine speed and load.
Note on display zones 3 and 4:
The period specifies the time between two voltage jumps in the lambda probe (e.g. rich - lean - rich) thereby providing a measurement basis for the ageing status of the lambda probe. If the specified time is exceeded, display zone 4 indicates = B1-P1 NOK.
(cont.)
If specification in display zone 3 or 4 is not attained:
Replace lambda probe 1 before catalytic converter -G108, bank 2.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.