Toyota Vitz (2010) 1KR-FE KSP130 DTC P0420

Tanveer Technical Support Specialist Pakistan Posted   Latest  
P0420 — Catalyst System Efficiency Below Threshold Bank 1
P0401 — EGR "A" Flow Insufficient Detected
P0403 — EGR "A" Control Circuit/Open
Check E

I have Toyota Vitz (2010) equipped with 1KR-FE engine that was showing DTC P0420 (Catalyst System Efficiency Below Threshold), after visual inspection I noticed catalyst was already removed, so I installed adapter on post O2 catalyst sensor as per attached pictures and did a road DTC P0420 was not existing any more but i got another EGR related DTC's P0401 & P0403 but when i removed O2 sensor adapter EGR DTC's cleared from PCM.

Please guide me how to deal with DTC P0420 as new Catalytic Converter cost me 400 $.

Why getting EGR related DTC'c when installing a adapter on O2 Sensor ? 

Robert Mechanic

P0 403 I would attack first and make sure that you do not have an open circuit. It could be an intermittent open circuit heat and vibration . I don’t see how EGR code would set an open circuit code for EGR. Next, I would check for flow EGR system. Most flow problems are not in the EGR itself but in the intake manifold right up by the EGR valve. I hope this helps :-) however your insufficient…

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Arsalan Service Manager
District of Columbia

I'm guessing that this is a 2010 Toyota Yaris in USA? Does this even have a EGR since I don't have info on VITZ?

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Tanveer Technical Support Specialist

Yes it is same like Toyota Yaris and equipped with 1KR-FE 1000cc Engine.

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Timothy Owner/Technician

Because the PCM expects to see a change in exhaust gases when EGR is operational. Since you've you've used what would be an illegal device to cheat emissions, you're getting nailed by the PCM because it does not see what changes it wants when EGR is commanded. A catalyst for a small Yaris here would be in excess of a thousand dollars US, so 400.00 isn't too bad.

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Tanveer Technical Support Specialist
Tanveer Delay

At second step slightly increased the diameter of adapter but got the same DTC'c, finally installed used catalytic converter that cost me 200 $ and my issue was resolved.

Delay Ð Awarded