Questions & Answers for: Volkswagen Golf p0420

...is "ON" and the guy at the shop told me that the code is 420. What is code 420? if the code is p0420 it means catalyst system efficiency below threshold (cylinder bank no.1) how can i fix the

2001 golf gti had fault code p0420 come up had new rear lamda done still p0420 so got new front lamda, code still come up so then got a new cat, then fault code p0420 and p0120 come up,, then had new ...

obd code 420 The P0420? if so, it means Catalyst System Efficiency Below Threshold (Bank 1). hope it can help you!__________ak90 key programmer