[FIXED] longtime lurker/ channel watcher p0154

Hello all,

I've watched the channel and read through the forums for help on many occasions, but this one seems beyond me.

I have a 2000 GMC k2500 HD (the old body style with the 5.7 Vortec). In October 2019, I was pulling a p0134 code. Performance was terrible. Flooring the gas pedal would make the truck move about as fast as a Yugo. At that time, I replaced both front o2 sensors but the ultimate issue was teflon tape had somehow gotten into my fuel filter and was blocking the flow. I replaced the fuel filter at that time and had no issues.

Fast forward to February 2020. I don't normally buy gas from Delta here in NJ, but I did. I noticed a CEL pop up and lousy performance. I didn't read any code at that time, but I put a bottle of injector cleaner in the tank and the CEL went away. A few weeks later, I had no choice but to stop at another Delta gas station. Since it was a different station, i thought nothing of it. Since then I've had a p0154 code pop up on the truck along with TERRIBLE performance.

I attached my scan tool to the truck and read live data. My bank 2 sensor 1 was pulling about .12mv constantly while bank 1 would fluctuate. I presumed the sensor was the culprit. I purchased a new Denso unit even though I had just replaced this exact sensor 4 months ago. I was still getting a bad reading. So I disconnected the sensor and checked the voltage on the harness. It was putting out a solid 12v with the ignition on. I checked for vacuum leaks, there were none, I then sprayed contact cleaner on the harness side and let it dry thoroughly before reconnecting the o2. So then I decided it had to be the oil filter, and I replaced that. That did not solve the issue either.

Looking closer at the live data. It appears my bank 2 sensor 1 sits at around .450mv and the bank 2 sensor 2 fluctuates. This bank is also running lean and the loop NEVER closes. Fuel trim is a steady 9.38% on both banks when applying throttle.



I'm at the point where I'm assuming something is either stuck in my fuel pump or that this brand new sensor is bad. I am going to perform a fuel pressure test tomorrow for further verification. I know exhaust leaks may cause this problem, but I don't have any of those either.

Do you have 450 mv on the signal wire, at the connector?

Bank 1 Sensor 2 at 60mv really sticks out to me. One bank richer than the other may also be a clue.

This makes me think of the possibility of an exhaust restriction even though you’re dealing with a circuit code.

Are you getting OL FAULT or are you just not going into fuel control?

In NJ my truck does not require emissions. Bank 2 has no catalytic converters while bank 1 does. I may remove bank 1 catalytic converter as well

I will check for bias voltage and fuel pressure tonight. When I rapidly tap the gas, bank 2 sensor 2 fluctuates but bank 2 sensor 1 sits around 450. I watched this video

with KOEO check scan data B2S1 reads 450mv... unplug the sensor. If the voltage now reads 0v, the sensor is bad. If it stays at 450mv, using a test light attached to battery negative, ground the signal wire (not the 5v ref wire) on the harness side. If voltage drops to 0 the wiring is good 02 is bad. If it stays at 450mv you have an open in the signal wire between connector and pcm.

you can also swap the B2S1 02 with the B1S1 02 and see if the problem has moved to B1. If it did the sensor is bad.