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2000 GMC Silverado 6.0L P0157 O2 Sensor Code: Causes, Fixes & Solutions

Model: 2000 2500 6.0L Silverado Fault Code: P0157 Posted: 2007-11-20 09:14

I've been dealing with a recurring P0157 code on my 2000 GMC Silverado 6.0L for over a year now. Despite replacing all oxygen sensors, the code keeps coming back—sometimes intermittently and sometimes persistently. Recently, I replaced my fuel pump, and the code disappeared for about two days before returning. Since then, my fuel economy has dropped significantly, making this issue both costly and frustrating. I've read that a faulty gas cap could trigger P0157, especially if there's an air leak in the system. Additionally, I have an open-air K&N intake installed, which led me to suspect possible oil buildup from the filter clogging my MAF sensor. As a test, I reverted to the stock air intake, but the P015-7 code reappeared. I'm now considering checking fuel pressure and looking for exhaust leaks or wiring issues. The P0157 code specifically refers to the second oxygen sensor on bank 2 (passenger side), located after the catalytic converter. I've confirmed that both post-catalyst O2 sensors are AC Delco AFS-106 models. I'm seeking advice on whether a resistance or voltage test of the sensor is worth doing before replacing it, and if there are other common causes for this code in 6.0L Silverado trucks.

Related fault codes
P0157
Comments (3)
Anonymous 2007-11-21 07:33

What is your fuel pressure reading? A low or inconsistent fuel pressure could be contributing to the P0157 code, especially when under load.

Anonymous 2007-11-21 08:17

I haven't tested fuel pressure yet—I don't have a gauge on hand. I've already switched back to the stock air intake, and even with that, the P0157 code remains active. This makes me think the issue might be deeper than just airflow or sensor contamination.

Anonymous 2009-03-23 05:35

Hi everyone—I'm new here and have the same P0157 issue on my 2002 GMC Yukon XL Denali 6.0L. The code only appears during full-throttle operation, especially when towing heavy loads. It's always P0157 and never any other code. I've reset it multiple times, but it returns under those conditions. My truck runs fine with the check engine light on or off. P0157 refers to oxygen sensor #2 on bank 2—this is the passenger-side sensor located after the catalytic converter. I’ve confirmed both post-catalyst sensors are AC Delco AFS-106 models. I'm now checking for exhaust leaks and inspecting wiring connections. Are there any diagnostic tests (like voltage or resistance checks) I can perform on the O2 sensor before replacing it? Any tips would be greatly appreciated!