Audi Workshop Service and Repair Manuals > A3 Mk1 > Power unit | Motronic injection and ignition system (4-cylinder turbo) | Mixture preparation system, electronic inj.,Gas | Servicing Motronic injection system | Checking ageing of Lambda probe before catalytic converter

Checking ageing of Lambda probe before catalytic converter

Special tools and workshop equipment required

t	Engine speed adjuster -V.A.G 1788/10-

t	Vehicle diagnosis and service information system -VAS 5052-

Test sequence

Note

Coolant temperature at least 80 °C.

–	Connect up the vehicle diagnostic and service information system -VAS 5052- and select the engine electronics control unit. Engine must be idling.

–	Select the function “Start basic setting” and confirm.

–	Enter “034” for “Display group number 034” and confirm.

–	Use the speed setting tool -V.A.G 1788/10- to set the engine speed to 2000 rpm.

–	Check the specification in display zone 4:

Note

This procedure may take several minutes.

	Display zones
	1	2	3	4
Display group 034: Diagnosis of Lambda probe ageing
Display	xxxx rpm	xxx °C	x.x	---
Display	Engine speed	Exhaust gas temperature	Dynamic factor	Diagnosis status
Operating range				Test OFF Test ON B1-S1- OK B1-S1- n.OK
Specification	2000 rpm	Greater than 350 °C	0.5...2.5	B1-S1- OK
Note

Note

Value calculated from engine speed and engine load

Note

The dynamic factor is an indicator for Lambda probe ageing. The lower the dynamic factor, the more advanced the ageing of the Lambda probe.

If the reading does not match the specification in display zone 3 or 4:

–	Perform a test drive to remove any residue from the Lambda probe and repeat the test.

If the reading does not match the specification in display zone 3 or 4 even after a test drive:

–	Replace the Lambda probe -G39-.

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