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2005 Chevrolet Silverado OBD2 Codes 0171, 0131, 0300, 1133: Lean Bank 1, O2 Sensor Issues, Misfire Diagnosis

Model: 05 Silverado Fault Code: P0131 Posted: 2008-03-28 14:26

Hello everyone, My 2005 Chevrolet Silverado has a check engine light activated with the following OBD2 diagnostic codes: - 0171: System too lean (Bank 1) - 0131: O2 sensor circuit low voltage (Bank 1, Sensor 1) - 0300: Random/Multiple Cylinder Misfire Detected - 0131 (Pending): O2 sensor circuit low voltage (Bank 1, Sensor 1) - 0171 (Pending): System too lean (Bank 1, Pending) - 1133: A/C pressure sensor high voltage or O2 sensor Bank 1 Sensor 1 sluggish (slow crosscounts, Pending) The spark plugs on the driver's side (Bank 1) show significant soot and black deposits compared to the passenger side. The truck idles smoothly when cold but becomes rough as it warms up—almost like a misfire is occurring—and the exhaust emits a sooty appearance. Performance at higher RPMs and overall mileage remains acceptable. Previously, the battery has died several times, prompting multiple charges. Could this have caused damage to the O2 sensor due to voltage fluctuations? I haven’t cleared the codes yet—assuming they will reappear since the idle issue persists. Any insights or troubleshooting steps would be greatly appreciated. Thanks in advance for your help!

Related fault codes
P0131P0171P0300P1133
Comments (8)
Anonymous 2008-03-28 15:24

Could a blown fuse related to the engine or O2 system be causing these issues? Are you certain your fuel pressure is within normal range?

Anonymous 2008-03-28 15:36

Thanks for the quick reply, Jeff. I'll check the fuses tomorrow. Not sure how to test fuel pressure with my current tools—will look into it when I get home.

Anonymous 2008-03-28 16:35

I've checked both 15A fuses labeled O2A and O2B—they're both intact. The fuse issue seems unlikely, but I'll inspect the driver's side O2 sensor to see if there are signs of a low-voltage fault. Could wiring or sensor failure be the root cause?

Anonymous 2008-03-28 23:24

Jeff—I found a similar post on another OBDII forum (link below). A user had identical symptoms and resolved them by replacing the Bank 1 O2 sensor. I’ve reached out to him for confirmation, though it’s not definitive. Is there a way to test an O2 sensor once removed—like with a resistance check? I’d rather avoid spending money on a replacement if it's not necessary. Link: http://www.obdii.com/forums/ubbthreads...#Post13600

Anonymous 2008-03-29 14:38

An O2 sensor resistance test is generally ineffective because these sensors operate based on voltage and signal response, not fixed resistance. A scope (oscilloscope) would provide a much more accurate diagnosis.

Anonymous 2008-03-31 16:39

Quick follow-up: Based on my current understanding, I plan to replace the O2 sensor on the driver's side (Bank 1). The dealer charges $135 for a Denso sensor, but I can find an OEM Bosch equivalent for about $50. From what I understand, many GM vehicles are equipped with Bosch O2 sensors. A technician advised that after installation, the fuel trim must be reset so the air-fuel ratio (AFR) matches the new sensor’s calibration. Is this correct? And will a genuine OEM Bosch sensor work properly in my 2005 Silverado?

Anonymous 2008-03-31 17:13

I strongly advise against using aftermarket O2 sensors—especially those from auto parts stores. Quality inconsistency is a major issue; many users waste time and money on these parts only to discover the sensor doesn’t perform as expected. If the part numbers match exactly between the original OEM and the replacement (e.g., same Bosch or NTK model), that might be acceptable—but such matches are rare. Why would GM use Denso if Bosch is cheaper and equally reliable? If the Bosch sensor isn't from a genuine GM cross-reference, it's likely subpar. I’ve seen forums where users replaced their O2 sensors with cheap parts and ended up chasing problems for weeks before realizing the issue was with the wrong part. If you're not confident in your diagnosis, avoid replacing components without solid evidence—this could lead to repeated failures.

Anonymous 2008-04-01 17:14

I recently purchased a Denso O2 sensor (actually $125) and had it installed by the dealer. They reset the fuel trim after installation. After driving about 20 miles, the truck runs smoothly—no rough idle or sooty exhaust. The technician noted that Bank 1 was previously running with a 17% fuel dump due to sensor inaccuracies. I’m hopeful this resolves the issue. Thanks for sharing, Jeff—I’ll update if any further issues arise.