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2004 GMC Denali with P0141 and P0161 After O2 Sensor Replacement - Diagnosis and Fixes

Model: 04 GMC Denali Fault Code: P0141 Posted: 2009-12-05 16:06

I recently replaced the O2 sensor on my 2004 GMC Denali due to a persistent P0161 fault code. After the replacement, the Check Engine Light turned off. However, just 20 miles later, both P0141 and P0161 codes returned. I suspect the new O2 sensor might be defective, but I'm confused as to why P0141 would appear—this code typically relates to the upstream oxygen sensor in the exhaust system. I've ordered a replacement O2 sensor, hoping it resolves the issue. What could be causing these recurring fault codes? Is there a possibility of an underlying problem like a failing catalytic converter or wiring issues?

Related fault codes
P0141P0161
Comments (8)
Anonymous 2009-12-05 17:11

What brand of O2 sensor did you install? GM trucks often trigger oxygen sensor faults when the catalytic converter is failing. It's worth checking if that component is the root cause.

Anonymous 2009-12-06 20:10

I installed an aftermarket universal O2 sensor and kept my original one as a backup. I also replaced the air filter, spark plugs, and changed the oil. After driving about 8 miles, the Check Engine Light came back on with P0161. Does this suggest a failing catalytic converter?

Anonymous 2009-12-07 06:00

I used a Bosch-brand O2 sensor—most 'universal fit' sensors are not reliable. I recommend using your vehicle's VIN to visit a GM dealership and get the correct OEM sensor. Clear the DTCs, then drive the vehicle and monitor if any codes return. Also check for blown fuses labeled 'O2 sensor' or related to the exhaust system.

Anonymous 2009-12-07 10:00

Thanks for the tip—I'll try that advice first. I hope it's just a blown fuse causing the issue.

Anonymous 2009-12-09 00:21

I eventually took my truck to the dealership, where they replaced two O2 sensors, cleaned the MAF sensor, and flushed out carbon buildup and debris. It was costly, but now all codes are cleared. Personally, I find Japanese-made vehicles more reliable in terms of long-term performance.

Anonymous 2009-12-09 06:25

It's frustrating that a six-year-old truck requires such extensive repairs! This seems like a conspiracy to me.

Anonymous 2009-12-09 23:10

It’s likely due to GM not receiving sufficient bailout funds from taxpayers—so they’re pushing for more repairs and part replacements.

Anonymous 2009-12-10 06:17

The issue predates the current tax breaks or buyouts. The parts were manufactured and installed over six years ago, and no special consideration was given at that time. It's simply a result of normal wear and tear. Many posts on this forum also mention similar issues with imported vehicles. This doesn’t reflect a conspiracy—it’s just the reality of vehicle longevity. If you're upset, blame the seller who recommended an inferior part or yourself for not seeking professional advice. Expertise comes at a cost—whether you have it or not, you’ll eventually pay for it. That has always been true and likely will remain so.