Help with P0156 & P0157 Codes

Getting the following lights after replacing both AF Upstream sensors, lower cats, upper cats and right bank defouler

No check engine light
Brake and ABS solid
Slip and FWD indicators flashing
(These lights only come on periodically)

Ran on OBDII, get P0156 Sensor Circuit bank 2, sensor 2
P0157 02 sensor circuit, low voltage, bank 2, sensor 2

I like learning how to track down and remedy but this is getting frustrating. Any help would be appreciated

 

Have you tried disconnecting the battery and walking away for 20-30 minutes. When replacing electrical sensors, sometimes the ECU needs to re-learn. In other words it still thinks the old sensors are still there. Also, it's generally recommended to replace ALL of the O2 sensors. As far as the brake, ABS, VSC and FWD lights flashing, that's separate. That's more than likely going to have something to do with wheel speed sensors. Did you actually replace catalytic convertors? Why if so?

 

Yes, I have tried disconnecting the battery more than a few times and leaving it disconnected for increasingly longer periods to no avail. I have replaced all of the O2 sensors, and cats. I am nearing 200,000 miles and this vehicle has served me well throughout 13 Midwestern winters, I was due to replace. Not only that, I have to worry about emissions testing in my home state .

 

Those are both circuit-related codes so have you verified the wiring? Getting both circuit codes on only one sensor would have me looking there first.

Especially with other random lights flashing, it definitely smells like a harness problem.

 

Next question would be: are these genuine Toyota parts, especially the sensors?

 

Where did you source your parts? And, what brand? Also, what was the impetus to replace? Was the exhaust system rusted out? These are things that are not typically "due to replace". I too have a 2011 with nearly 200K and have to comply with state emissions. Never even a thought or worry of not passing, nor do I need or even consider replacement.

 

I was just looking for help from the community tracking down a new problem that I have encountered. The harness problem makes sense to me, thank you for that input. Visually there is no damage or corrosion whatsoever so I am off to check some volts.

I have modified this vehicle. I have lifted it, put bigger tires on it, aftermarket Method wheels, wrapped it, replaced all factory lights with Morimotos, cut half of the front end off to install a CBI front bumper, reservoir cover and skids, Prinsu roof rack, and ceramic tinted the living daylights out of it. YES, my exhaust was leaking. I live in a rural area where they throw salt around like it's going out of style. I have used Magnaflow, MBRP and Bosch to remedy that and to make noise. I like the sound of the exhaust very much. What I like even better is that as a female 4Runner owner, I have officially distanced my self from every baseball cap wearing soccer mom perpetually doing the Starbucks and Target run. I really love my vehicle and it has never let me down. Modification is enjoyable to me, but obviously not without some snags. Clearly I'm not a professional, this has become my hobby as I am a bit of a gearhead since I was a kid (thanks Dad).

 

No need to get all defensive. The reason I asked about brands is because these vehicles don't always play well with non-OEM. Specifically the O2 sensors. If you installed Bosch, they might be giving you problems. OEM is Denso. You ask questions, and sometimes we ask questions. That's how a forum works.

 

Truth right here. Once vehicles got the more advanced O2 sensors ~20 years ago, we stopped using anything but OEM at any shop I worked at. If you haven't done this it could still be your issue... when they go, it's not uncommon to burn out the heating element and throw off the sensor but I'd still verify wiring first.