# Post Cat Oxygen sensor bypass DIY (only costs about 5-10 bucks)



## vdubnick (Nov 29, 2004)

*disclaimer: This worked fine for me, I am a professional, and can only guarantee the work of myself, i am not responsible for your mistakes. Also check your local laws for the legalities of a gutted catalytic converter. Otherwise this is for off road use only.

As for the post cat fix, this voltage divider setup should work, once the car goes into closed loop mode, the heater circuit has constant power. And the ECU does not draw any significant current, so it is just "seeing" the voltage. 








ECU has gone through a full cycle and no soft codes or CEL, all 7 rediness checks are good, so it would pass emissions just fine.
As far as the large resistor, i just used qty. 50 690 ohm 1/4 watt resistors in parallel.
Forgot to add, this fix is for a 98 VW Jetta GL with the 2L ABA engine. Im sure it will work on many other models too.




_Modified by vdubnick at 4:59 PM 7-11-2009_


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## coreyj (Aug 18, 2006)

interesting.. you should check to see if this would work on a 1.8t


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## vdubnick (Nov 29, 2004)

^ best to just try it yourself. If you do it the exact way as I have you will not have any chance of harming the ECU or anything else... its worth a shot.


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## stopcallinmefrank (Jul 8, 2009)

*Re: (vdubnick)*

hmmm wish i would have payed more attention in math class all these letters and numbers and fractions















wouldnt it be easier to just say..."hey if you wire these two wires together and unplug this one....you got it made man!!!










_Modified by stopcallinmefrank at 10:23 PM 7-11-2009_


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## vdubnick (Nov 29, 2004)

^ yeah, that is what the diagram is for.... not rocket science, just follow the picture.


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## vdubnick (Nov 29, 2004)

here is the module








it plugs directly in, no wires to run








can be secured with a zip tie









If anyone wants to buy one, id be willing to make one for you at a price. pm me if interested.

p.s. still no CEL or soft codes, module works great!


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## james-euro (Jan 18, 2009)

vdubnick said:


> here is the module<br><IMG SRC="http://img.photobucket.com/albums/v215/vdubnick/prepaint013.jpg" BORDER="0"><br>it plugs directly in, no wires to run<br><IMG SRC="http://img.photobucket.com/albums/v215/vdubnick/prepaint014.jpg" BORDER="0"><br>can be secured with a zip tie<br><IMG SRC="http://img.photobucket.com/albums/v215/vdubnick/prepaint015.jpg" BORDER="0"><p><br>If anyone wants to buy one, id be willing to make one for you at a price. pm me if interested.<p><br>p.s. still no CEL or soft codes, module works great!


i know this is an old thread have you made any more of these willing to help me figure this out


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## azjjrp (Jul 10, 2015)

*O2 Sensor Bypass Question*

good afternoon my friend, i understood almost all the diagram, i just have a question... what is this little sprinkle between terminal n1 and n2?








if it is a resistor or something, can you give me the specifications please?, i didn't quite understood the in the diagram.


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