So I bought LOLM3's old Borla a while back & everything's been great except CEL P0137 & the VSC light keeps popping up on me every 30-40 miles. I have a 12' with 20k miles on the odo.

P0137:
O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 2)

It has secondary cats welded on along with these type of O2 defoulers so the O2 sensors can reach the re-located bungs (except they're welded, not screwed on):


I've swapped sensor 1's with bank 2's sensor & even went ahead & replaced it with a brand new one, same code keeps popping up . Resetting the light is getting old & inspection time is coming up!

There are no audible exhaust leaks as far as I can tell, would a minor leak throw the CEL?
Should I cut out the secondary cats & replace with straight piping like how the exhaust was originally made?

I'll get some actual pics of the setup later, any suggestions/help is appreciated!


***UPDATE 10/15***
Finally had a chance to run by a muffler shop......chopped off the cats & defoulers/O2 extenders, problem solved! Turns out the defouler/extender on the bank 1 side was welded very ****ty, it had a tiny hole exposed causing a leak near the sensor. How LOL M3 didn't have a CEL, I have no idea but problem solved. Thanks every one!

















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Also possible causes from Googling:
- Rear Heated Oxygen Sensor harness is open or shorted
- Rear Heated Oxygen Sensor circuit poor electrical connection
- Faulty Rear Heated Oxygen Sensor
- Incorrect fuel pressure
- Faulty fuel injectors
- Exhaust manifold leaks

 

Im sorry to hear this. When I hear stuff like this it makes me nervous to get an exhaust. Hope you get it resolved. Who did the install ?

 

Exhaust is straight forward and shouldn't cause any cell. You would only need those bungs if the primary cats are gutted/removed. Cut out the high flow cats and move these sensors back to it's original location should fix it in my opinion

 

Haha I bought LOLM3's PPE headers and its throwing all sorts of codes.. its just bad luck.

 

Thanks, I had my dad's friend's shop do the install.


I'll give it a shot, I PM'd LOL M3 and he said he didn't have any issues with this setup on his own car. I was hoping I wouldn't have to spend anymore $ getting this cleared up. I'm thinking maybe the sensor isn't getting enough exhaust gases to read? But then the bank 2 sensor has the same defouler on it but no cel there :/.


Lol yeah I actually started this thread after I saw the one you started.

 

remove that pipe and your problems will be solved, if you remove the O2 sensor from the path of exhaust flow it will read less O2 the result will be low voltage the ecu will try to make it switch by adding more fuel and when it does not. you will get this code.

the pipe may work on some cars and not others, toyota's don't respond well to this method cat delete most of the time you will need some kind of micro processor controlled O2 sensor delete.

 

Thanks for the tip, I guess I'll give this a shot.....I touched on this in my comment above but I guess I don't have too much to lose. Shouldn't be too much to hack off the cats and get new bungs:

 

keep the cats remove the tubes. put the rear 02 Sensors at a 45 degree angle.

 

Running a Borla here and have no issues my bro in law also has Borla and no issues there.

Maybe they pinched the wire but you said you tried new o2 sensors so doesn't make sense.
Buy yeah remove the fowlers and try that those are only good for not running any cats