# Unitronic stage 2 P0420 P0141 dtc's.



## vwmeater (May 3, 2004)

Autowerkes DP and Uni stage 2. Stage 2 cost me a clutch at 20k total miles. Torque is great when the CEL is not lit. Pulls nice from 2000rpm to 5000rpm! Still plagued with intermittent CEL(once every 2 driving cycles) P0420 cat efficiency below threshold and P0141 O2 sensor B1S2 heater malfunction. Wrote Uni about it and they told me that P0420 is a known issue and they are working on a flash update for it. So far tried new O2 sensor; without success. Harness is ok. O2 sensor spacers only worsened the P0141 dtc occurence but P0420 happens less often. Autowerkes DP did not fit right so I had to cut and weld. Also, the #2 O2 sensor is located more upstream on the downpipe. It could be running too hot maybe... I'll try relocating the #2 sensor and install a mini cat spacer. Someone got a solution for these dtc or encountered a similar problem? Does Unitronic downpipes gives similar DTC's? Thank you!


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## gavinthorp (Sep 27, 2018)

Have you reflashed recently? I was getting P0420 but they released an update around January. Try flashing to stock then back to Stage 2, the software should update automatically. 
I have the Uni DP so I can't promise that it'll solve your problem, plus I never got the P0141, but it's worth a shot.


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## mk6ChrisKing (Oct 7, 2019)

My bois are Unitronic stage 2 with the dp from Unitronic as well, they don't have any codes. I will be soon

I have heard a lot of bad comments about autowerks and there dps and such. The o2 sensor issue is a known problem with the auto werks dp, everyone I know who was it ( three people ) have the same code and or check engine light and they don't bother to clear it anymore. 


Keep us updated


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## mk6ChrisKing (Oct 7, 2019)

You said torque is good when cel light is not lit? Could you explain what the issue is with the cel being on and the torque being delivered?


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## vwmeater (May 3, 2004)

gavinthorp said:


> Have you reflashed recently? I was getting P0420 but they released an update around January. Try flashing to stock then back to Stage 2, the software should update automatically.
> I have the Uni DP so I can't promise that it'll solve your problem, plus I never got the P0141, but it's worth a shot.


Just did that this evening. I was not aware that Uni released the corrective flash. Flashed back to stock and then stage 2. I also removed the O2 sensor spacer. Went for a ride with a couple WOT and so far so good! Maybe the O2 sensor was too far from the exhaust flow with the spacer and the ECU had a hard time regulating the O2 sensor heater temperature.

Thanks!


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## vwmeater (May 3, 2004)

mk6ChrisKing said:


> You said torque is good when cel light is not lit? Could you explain what the issue is with the cel being on and the torque being delivered?


DTC was usually triggered while at WOT and I could really feel the power cut down instantly. ECU going into protection mode. Driving around with the CEL it was obvious torque kicked in smoother and less agressive. No kick in the butt.


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## mk6ChrisKing (Oct 7, 2019)

vwmeater said:


> Just did that this evening. I was not aware that Uni released the corrective flash. Flashed back to stock and then stage 2. I also removed the O2 sensor spacer. Went for a ride with a couple WOT and so far so good! Maybe the O2 sensor was too far from the exhaust flow with the spacer and the ECU had a hard time regulating the O2 sensor heater temperature.
> 
> Thanks!


Oh sounds like its all good now with the update? Do some more pulls and get back to me. Yeah that sounds about right, the car went into limp mode at wot. 

I shouldn't have that problem since I am doing it in a few days and the update will already be present I assume.


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## vwmeater (May 3, 2004)

Well... I'm not riding much these days, blame covid. I did 200 miles and still no dtc! CEL went on every 2 driving cycles before. I drove almost a year erasing DTC's almost every day! I'm really glad it's now solved for good! I'll have a couple O2 spacers for sale soon! 😆


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