Testing lambda probe (before catalytic converter) for ageing — AUDI
Testing lambda probe (before catalytic converter) for ageing on Audi: factory workshop procedure for engines ALZ, ANA, APT, ARG.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 32 workshop diagrams for ALZ
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
ALZ
Special tools and workshop equipment required
V.A.G 1788/10 Engine speed adjuster
VAS 5051 and VAS 5051/1
or
V.A.G 1551 and V.A.G 1551/3 A
Test requirement:
Coolant temperature at least 80 °C =>Display group 004, Display zone 3.
Test sequence
Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551). Select engine electronics control unit by entering the address word "01" => Page
01-12
; when doing this the engine must be running at idling speed.
Rapid data transfer
HELP
Select function XX
Indicated on display:
Enter "04" to select "Basic setting" and confirm with Q key.
Introduction of basic setting
Q
Enter display group number XXX
Indicated on display:
Enter "034" for Display Group 034 and confirm entry with Q key.
System in basic setting 34
⇒
1
2
3
4
Indicated on display:
Set engine speed at between 3000 and 4000 rpm using the speed regulator V.A.G 1788/10.
Continue 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 of lambda probe ageing
Display · xxxx rpm · xxx °C · x.x s · ---
Indicates · Engine speed · Exhaust temperature · Cycle duration of / lambda probe (before catalytic converter) · Status of diagnosis
Range · 0...6500 · 70...850 °C · 0...5.0 sec. · Test OFF / Test ON / B1-P1 O.K. / B1-P1 n. O.K.
Specification · 3000...4000 rpm · Higher than 250 °C · 0.0...5.0 sec. · B1-P1 O.K.
Note · If specification is not attained, refer to / Page 24-109
Note on display zone 2:
Value calculated from engine speed and engine load.
Note on display zones 3 and 4:
The cycle duration of the lambda probe indicates the time between two voltage pulses (e.g. rich - lean - rich). It is therefore a means of evaluating lambda probe ageing (i.e. the condition of the lambda probe). If the indicated cycle duration is exceeded, "B1-P1 n. OK" will appear in display zone 4.
Further notes
If the readout in display zone 3 or 4 does not match the specification:
Take car for a test drive to free lambda probe of any deposits, then repeat the test.
If the readout in display zone 3 or 4 still does not match the specification even after the test drive:
Replace the lambda probe 1 (before catalytic converter) -G39.
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.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.