I recently brought my 2003 A6 in for emissions testing and it failed due to the following codes:

P0421
P0741

Can anyone tell me what these codes mean? It would be much appreciated. Thank you in advance.

 

P0421-Passenger side catalytic converter efficiency below threshold
P0741-Torque converter clutch circuit

I would suggest the following:

P0421 - Search for "spark plug anti fouler trick"
P0741 - Drain and fill your transmission with correct fluid.

These suggestions are temporary in nature....

 

code po741 is indeed a torque converter code , but there may be other issues, feel free to visit levelten.com to see a 100%fix.

 

check this one out also