Code P0137

I’m posting thing here cuz it’s the last thing I can think off going to get rid of this code once and for all. So some one tried stealing my cats but all they managed was to cut the downstream o2s. After all that I got the PO137.
So I’ll list what I’ve done so far for the sake of marking answers off the table.
Replaced o2s with Denzo o2s (even the upstream on the bank 1 side just in case)
Tested with voltmeter the o2 plugs to see if I get the right voltage on both banks with the truck running
And voltage was the same
Hooked up scanner to see the data and the signal would go to 0 every few seconds while bank 2 had steady voltage.
I swapped o2s between bank 1 and 2 just to make sure the o2 worked properly and the problem stayed on bank 1.
Tried making a jumper between signal wires to make both sides read the same and it just gave me a high voltage code lol.
Checked exhaust for cuts and nothing
I checked the MAF with the scanner to see if it was operating right and yes it’s fine.
I also have hywett tech air pump bypass (in case that makes a difference)
So my last option would be is to delete both downstream o2s as if I was getting cat backs or custom exhaust and flash the ECU to get rid of the code.
I’m open to any and all suggestions at this point

 

Exhaust leak test with shop vac on tailpipe and use soapy water sprayed on flanges. How are your fuel trims? Running rich...contact Hewitt and see if the p0137 is a byproduct of their bypass may need updated.

 

I haven’t checked fuel trims, I’ll have to see if I can do it with my cheapo scanner lol idk what it’s called in the live data page

 

+1 on checking for exhaust leak

 

I borrowed one of those fancy smoke machines, I’ll check today, might as well check for vacuum leaks while I’m at it

 

As I mentioned above. If you have a shop vac. You can reverse the hose so it blows out through the hose.
You can hook it up to the exhaust exit, turn it on and spray the flanges with soapy water. It was the only way I could find a leak on my son's car.

 

We have used a short chunk of garden hose as a stethoscope to find exhaust leaks when a shop vac isn’t available. Not quite as good, but still pretty good…

 

If your 02 leads were cut and the truck was started, there is a possibility that the emissions ECU was shorted out and damaged. Look around this forum and a couple of others and you can find folks who had that issue.

Here in the stolen cat capital, it’s common to hear about folks having to replace the ECU in addition to the cats.

 

So after checking for exhaust leaks and couldn’t find any, I read on here about switching o2 plugs from bank 1 to bank 2. I did it to confirm exhaust and maybe bad ECM and the same code came back P0136 so that confirms there’s no leak other wise it would have jumped to bank2s2. So I’m convinced that the ECM is toast but I’m gonna double check

 

So while the plugs were switched B2S2 worked just fine but I still got the low voltage on B1S2, I went ahead and soldered a new o2 plug to see if it would fix the signal issue and nothing....
Should I run my own signal wire? Im lost on what to do since idk how to test the ECM/ECU. side note B2S2 while it was plugged to the B1S2 sensor it got perfect signal out of it.

 

Latest, I soldered a new plug and nothing. I routed a new wire to the ECM and nothing. No new ECM yet I really don’t know what else to try

 

Thanks everyone for the help, it wound up being the ECM. I got one from flagship 1 Plug and play ready to go.

 

Glad you figured it out!