With Manufacturer's Scan Tool

Catalytic converter, checking

Special tools, equipment, test and inspection devices; required accessories





- V.A.G 1551 scan tool

Note: The VAG 1552 system tester may also be used in place of the V.A. G 1551 scan tool, except that no printout can then be made.





- V.A.G 1551/3 cable

Test sequence
- Connect VAG 1551 (or VAG 1552) scan tool. Leave engine running and select engine control unit using "address word" 01.

Diagnosing the aging of oxygen sensors (sensor dynamics)





Indicated on display
- Press keys "0" and "4" for function "start basic setting" and acknowledge entry with "Q".





Indicated on display
- Press "0", "3" and "4" for display group 34 and acknowledge with "Q".





Indicated on display (1-4 "display fields)
- Press brake pedal and hold.

Note: The engine control unit will increase the engine speed.

- Check specifications in fields 1-4.
If the diagnosis was started by the engine control unit, the field 4 will jump from "Test OFF" to "Test ON."

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Display Fields

- Press - button.
- Check DTC memory.
- Read readiness code.
- If fault memory has been erased or engine control unit was separated from positive voltage supply, readiness code must be regenerated.
If the indictor behaved as described:
- Release brake pedal.
- Press C button.

Diagnosis of catalytic converter

Note: This diagnosis will only exit if the diagnosis of the aging of the oxygen sensors has already been completed successfully.





Indicated on display
- Press "0", "4" and "6" for display group 46 and acknowledge with "Q."





Indicated on display (1-4 " display fields)
- Press brake pedal and hold.

Note: The engine control unit will increase the engine speed.

- Check catalytic converter conversion (amplitude ratio) in field 3:
Specification: 0.50 maximum
- Let engine run at higher speed until "Cat B1 OK" is displayed in field 4.
If the diagnosis is started by the engine control unit, field 4 will jump from "Test OFF" to "Test ON."

Note: Diagnosis of the catalytic converter lasts about 100 seconds.

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Display Fields

If the indicator does not behave as described:
- Press - button.
- Check DTC memory.
If the indicator behaves as described:
- Release brake pedal.
If "Cat B1 OK" is displayed in field 4:
- Check DTC memory.
- Read-out readiness code.
- If fault memory was erased or engine control unit was separated from positive voltage supply, readiness code must be regenerated.
If the specification "Cat B1 OK" is attained:
- Press - button.
- Press "0" and "6" for function "end output" and acknowledge by entering "Q"
- Turn off ignition.