Emissions Fail :( Help! - CEL P0420

[Psyco_Kitty]

So I recently bought me a new (new to me at least) 2003 Volkswagen GTI 1.8t Tornado Red anyways... I am trying to pass emissions testing (State of Oregon) and get the car registered. So heres where the problems started...

I took it to DEQ to do an emissions test and it failed, the tech said that I needed to do a drive cycle to put all of the sensors in a ready state. I was working with radio and pulled the battery lead so that was probably why the sensors weren't ready. So I drove to Portland (50 mi round trip) and figured that would complete the drive cycle, then the CEL came on... P0420 Catalyst System Efficiency Below Threshold (Bank 1).

So I reset the CEL (this also resets the Drive Cycle) and drove it 100+ miles, all systems are ready except the following according to DEQ:

Catalyst: Incomplete
EGR System: Incomplete

How can I change these to the ready state and pass emissions?

[.:S]

If you have vcds, it will guide you through setting the readiness.


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[NCdub91]

P0420 usually means a bad catalytic converter.

[Psyco_Kitty]

I dont have VCDS.... I really need to invest in it. Could I use VCDS-lite to set the monitors to ready? I have a OBDII->USB device and could just download the shareware VCDS...

[mk3_vdub]

P0420 usually means a bad catalytic converter.

cat's getting clogged or going bad is kinda rare. usually its just the sensor needing replaced

usually my readiness codes are reset after 2-3 trips where the car is turned off/on again

[Psyco_Kitty]

Turns out that someone put a test pipe on the car and took out the cat entirely. I was able to pass emissions like 5th time . I just ordered a wheel spacer so hopefully that should fix the P0420 I've been throwing.

[Miller7204]

I just ordered a wheel spacer so hopefully that should fix the P0420 I've been throwing.

A wheel spacer? Do you mean an O2 sensor spacer?

[Psyco_Kitty]

Yes, and oxygen spacer... my bad Hopefully it will fix the problem, other people said it's worked for them, so why not. If that doesn't work, the spark plug arrestor mod would be my next shot.

A wheel spacer? Do you mean an O2 sensor spacer?

[Miller7204]

Yes, and oxygen spacer... my bad Hopefully it will fix the problem, other people said it's worked for them, so why not. If that doesn't work, the spark plug arrestor mod would be my next shot.

Let me know if it works I had this code but it never came back but now I've got 3 other codes related to my first 02 sensor so this might be a solution.

[Psyco_Kitty]

Spacer didn't work... I think I might need an angled one :/

[Miller7204]

Spacer didn't work... I think I might need an angled one :/

Did you go with the 42DD spacer?

[Psyco_Kitty]

I didn't want to spend the $40+ on the 42DD spacer, so I opted for a cheaper eBay 90 degree elbow spacer.

Like the one below... $19.25 ebay


Hopefully it works!

[Psyco_Kitty]

Fingers crossed... but this thing seems to be working great now, just put 300 miles on it with no CEL. Seems to have done the trick!

[jose porras]

16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
Possible Causes
Leakage in Intake and/or Exhaust System
Catalyst faulty
Oxygen Sensor(s) faulty
Oxygen Sensor(s) Control faulty
Possible Solutions
Check Intake and Exhaust System for Leaks
Check Catalyst
Check Oxygen Sensor(s)
Check Oxygen Sensor(s) Control
Perform Oxygen Sensor(s) Aging Check
Special Notes
For 1.8T's experiencing this fault code, this thread may be useful: http://forums.vwvortex.com/zerothread?id=663057

[Cryspimp2005]

you need a new cat

[vdubkid4life]

you need a new cat

Reading>you

[Psyco_Kitty]

No Cat -> P0420 CEL -> -> Research -> 90 degree ebay o2 spacer (~$20) ->= Problem Solved

use the google my friends

[Psyco_Kitty]

Catalyst System; Bank 1: Efficiency Below Threshold
Possible Causes
Leakage in Intake and/or Exhaust System
Catalyst faulty
Oxygen Sensor(s) faulty
Oxygen Sensor(s) Control faulty
Possible Solutions
Check Intake and Exhaust System for Leaks
Check Catalyst
Check Oxygen Sensor(s)
Check Oxygen Sensor(s) Control
Perform Oxygen Sensor(s) Aging Check
AFTERMARKET DOWNPIPE WITH CAT DELETE
Special Notes
For 1.8T's experiencing this fault code, this thread may be useful