Catalytic Converter: Testing and Inspection

Three-Way Catalytic Converter (TWC), checking
Special tools and equipment





^ V.A.G 1551 Scan Tool or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
^ V.A.G 1788/10 Engine speed adjuster

Checking sequence
- Connect V.A.G 1551 (V.A.G 1552). Start engine and select engine control module with "Address word" 01.





Indicated on display
- Press -0- and -4- buttons to select "Introduction of basic setting" and confirm entry with -Q- button.





Indicated on display
- Set engine speed to 1800 to 2200 rpm using speed regulator V.A.G 1788/10.
- Press -0-, -3- and -4- buttons to select "Display group number 34" and confirm entry with -Q- button.





Indicated on display: (1 to 4 = Display fields)
- Maintain engine speed at 1800 to 2200 rpm until display in display field 4 jumps from "Test OFF" to "Test ON".
^ Catalyst temperature in display field 2 must be between 350 and 500° C.
- Continue to maintain speed at 1800 to 2200 rpm until "B1-P1 OK" appears in display field 4.
- Press -C- button.
- Press -0-, -4- and -6- buttons to select "Display group number 46" and confirm entry with -Q- button.





Indicated on display: (1 to 4 Display fields)
- Maintain engine speed at 1800 to 2200 rpm until display in display field 4 jumps from "Test OFF" to "Test ON".
^ Catalyst temperature in display field 2 must be at least 350°C.
- Check amplitude ratio in display field 3.
^ Specification: max. 0.4
- Continue to maintain engine speed at 1800 to 2200 rpm until "Cat B1 OK" appears in display field 4.
If "Cat. B1 not OK" appears in display field 4:
- Check Diagnostic Trouble Code (DTC) memory.
If the specification "Cat B1 OK" is obtained:
- Press (arrow) button.





Indicated on display
- Press -O- and -6- buttons to select "End data transfer" function and confirm input with the -Q- button.