Question

2004 Mitsubishi Lancer Ralliart 2.0L with engine code P0421, what needs to be fixed?

Answer 1

You must replace the catalytic converter. There is a factory service recall for this problem. You should contact your Mitsubishi dealer.

P0421 MITSUBISHI - Warm Up Catalyst Efficiency Below Threshold- Cylinders 1-4
Read more: https://www.autocodes.com/p0421_mitsubishi.html