Skoda Workshop Service and Repair Manuals > Octavia Mk1 > Drive unit | 1.4/55 kW Engine - Injection | Mixture preparation system, electronic inj.,Gas | Check for proper operation | Testing lambda probe and lambda control after catalyst

Testing lambda probe and lambda control after catalyst

t	Only use gilded contacts to repair contacts 3 and 4 in the lambda probe plug connection.

Special tools, test equipment and aids required

t	Vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3, 3A, 3B oder 3C-

t	Handheld multimeter, e.g. -V.A.G 1526 A-

t	Measuring tool set, e.g. -V.A.G 1594 A-

Test condition

l	Fuse 43 must be o.k.

l	Battery voltage at least 11.5 V.

l	The exhaust system between the cylinder head and the catalyst must be tight.

l	Coolant temperature at least 80°C ⇒ measured value block 004; display block 3.

Check for proper operation

–	Check display groups 031, 036 and 037 → Chapter.

If the specified value is not reached:

–	Conduct a test drive in order to eliminate any residues on the lambda probe and repeat the test.

If the specification is also not shown in the display field after a test drive:

Testing heater

–	Read measured value block and display group 041 → Chapter

If the specified values are not reached:

–	Test resistance of voltage supply for heater and cables to -Z29- (specified resistance 1...5 Ω) → Current flow diagrams and Fitting locations.

Test basic voltage

–	Disconnect the 4-pin plug connector from the lambda probe downstream of catalytic converter -G130--arrow-.

–	Set the multimeter for voltage measurement and connect to contacts 3 + 4 of the connector at wiring loom to control unit.

–	Start engine and measure basic voltage specified value: 0.400...0.500 V.

–	Switch off ignition.

If the specified value is not reached:

–	Check lambda probe wire downstream of catalytic converter → Current flow diagrams and Fitting locations

If the specified value is reached:

–	Replace lambda probe after catalyst -G130-.

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