Three Way Catalytic Converter (TWC), checking

Special tools, testers and auxiliary items required 

• Fault Read Out Device V.A.G 1551 or Vehicle Diagnosis, Testing and Information System VAS 5051B

Fig 1: V.A.G 1788/10 Speed Adjuster Tool

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Speed Adjuster Tool V.A.G 1788/10 (only engine code AWD, AWW)

Test sequence 

• Connect Fault Read Out Device V.A.G 1551 and select engine electronics control module with "Address word 01". Engine must run at idle for this. Connect fault read out device and select engine control module.

Scan tool display:

• Press buttons 0 and 4 for function "Initiate basic setting" and press Q button to confirm input.

Scan tool display:

• Press buttons 0 3 and 4 for the "Display group number 34" and press Q button to confirm input.

Scan tool display: (1 to 4 = display fields)

Engine code AWD, AWW 

• Adjust engine speed with Speed Adjuster Tool V.A.G 1788/10 to 1800 to 2200 RPM:
• Hold speed at 1800 to 2200 RPM until display in display field 4 goes from "Test OFF" to "Test ON". Catalytic converter temperature in display field 2 must be between 350 and 500 ° C.
• Continue to hold speed at 1800 to 2200 RPM until specified value "B1S1 OK" is shown in display field 4.

Engine code AWP 

• Press brake pedal and hold firmly.
• Press gas pedal into wide open throttle (WOT) position. The engine speed is raised to approx. 2300 RPM by engine control module.
• Hold brake and gas pedal down until display in display field 4 goes from "Test OFF" to "Test ON". Catalytic converter temperature in display field 2 must be between 350 and 500 ° C.
• Continue to hold brake and gas pedal until specified value "B1S1 OK" is shown in display field 4.

• Release brake and gas pedals.

Continued for all engine codes 

If reading does not result as described:

• Check DTC memory.
• Read readiness code.
• If DTC memory was cleared or engine control module disconnected from voltage supply, readiness code must be regenerated.

Reading results as described:

• Press C key.
• Press buttons 0 4 and 6 for "Display group number 46" and press Q button to confirm input.

Scan tool display: (1 to 4 = display fields)

Engine code AWD, AWW 

• Hold speed at 1800 to 2200 RPM until display in display field 4 goes from "Test OFF" to "Test ON". Catalytic converter temperature in display field 2 must be at least 440 ° C.
• Continue to hold speed at 1800 to 2200 RPM until specified value "Catalytic convert B1 OK" is shown in display field 4.
• Remove Speed Adjuster Tool V.A.G 1788/10 from gas pedal.

Engine code AWP 

• Press brake pedal and hold firmly.
• Press gas pedal into wide open throttle (WOT) position. The engine speed is raised to approx. 2300 RPM by engine control module.
• Hold brake and gas pedal down until display in display field 4 goes from "Test OFF" to "Test ON". Catalytic converter temperature in display field 2 must be at least 440 ° C.
• Continue to hold brake and gas pedal until specified value "Catalytic converter B1 OK" is shown in display field 4.

• Release brake and gas pedals.

Continued for all engine codes 

"Catalytic converter B1 not OKB" shown in display field 4:

• Check DTC memory.
• Read readiness code.
• If DTC memory was cleared or engine control module disconnected from voltage supply, readiness code must be regenerated.

If specified value "Catalytic converter B1 OK" :

• Press → key.

Scan tool display:

• Press buttons 0 and 6 for function "End output" and press Q button to confirm input.
• Switch off ignition.