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2004 Chevy Silverado 2500HD 6.0L Check Engine Light: P0300, P0101, P0155, P0332 Codes - Diagnosis & Fixes

Model: 04 2500HD 6.0L Fault Code: P0101 Posted: 2019-01-02 22:30

Hello! I'm new to this forum and seeking help with my 2004 Chevrolet Silverado 2500HD 6.0L truck. The check engine light has been on since I purchased the vehicle a few months ago, and it's showing the following diagnostic trouble codes: - P0300: Random Misfire Detected - P0101: Mass Airflow (MAF) Sensor Signal Range/Performance - P0155: Oxygen (O2) Heater Circuit Fault (Bank 2, Sensor 1) - P0332: Knock Sensor 2 Circuit Low Input (Bank 2) The truck still drives smoothly and performs well under normal conditions. I've already replaced the MAF sensor, air filter, spark plugs, and ignition wires. I'm wondering if one issue might be causing multiple codes. While P0332 seems unrelated to the misfire-related codes (P0300), I'd like to understand whether these are interconnected or if they point to separate problems. What should I check first? Any guidance on prioritizing repairs would be greatly appreciated.

Related fault codes
P0101P0155P0300
Comments (9)
Anonymous 2019-01-03 13:49

Start with addressing the P0155 code before moving to P0101, especially after installing a new MAF sensor. Refer to this forum's troubleshooting guide for detailed causes and solutions. Note that P0101 can contribute to drivability issues if unresolved.

Anonymous 2019-01-11 16:04

I'm focusing on resolving the P0155 code first. I haven't yet tested the O2 sensor heater resistance, but I suspect it's faulty. I have a question about Denso O2 sensors: The one at AutoZone costs around $90, while Amazon offers a similar model for roughly half that price (https://www.amazon.com/Denso-234-4669-O...B00199FCU4). The listing appears legitimate, though there's one negative review that's making me hesitant. Are the Denso sensors on Amazon genuine or knockoffs? I've found them at similar prices on two other websites — one specializes in Denso products only. Also, since I can get two units for the price of one, is it worth replacing both upstream O2 sensors as a pair? Any advice would be helpful.

Anonymous 2019-01-11 17:16

Consider checking rockauto.com for reliable and affordable parts options.

Anonymous 2019-01-12 07:33

Do you have access to diagnostic tools like a DVOM or scan tool? I recommend sticking with OEM-quality O2 sensors — part number 12572705 (AC Delco, superseded by 213-1161). While I use Amazon for parts, it offers excellent customer support and fast returns. As a Prime member, I get two-day free shipping. Rock Auto is slightly cheaper but has mixed reviews — their customer service is limited to email with slow responses. I've ordered from them multiple times without issues. Price comparison: Rock Auto at ~$56, Amazon at ~$58. Amazon's return policy and support are top-tier.

Anonymous 2019-01-12 08:03

How many miles does your truck have? If it's around 100k miles, I'd recommend replacing both front O2 sensors. Wait until the P0300 code is resolved before replacing the MAF sensor. After clearing all codes and driving normally, monitor for any return of errors. Are there noticeable driveability issues — such as misfires, rough idle, or engine noise? GM trucks have known intake gasket problems. A good scan tool would allow you to analyze STFT/LTFT values, O2 sensor response, and misfire counters for deeper insights.

Anonymous 2019-01-12 08:15

Addendum: P0155 refers to Bank 2 Sensor 1 — located on the passenger side. Check the connector for water intrusion from the AC evaporator. If multiple cylinders are experiencing misfires, dirty or clogged fuel injectors could be a factor. The only definitive way to confirm this is through monitoring misfire counters using a scan tool and performing an injector drop test. A fuel system cleaner like Techtron Total Fuel Cleaner may also help improve performance.

Anonymous 2019-01-13 14:48

I tested the heater wire resistance on Bank 2 Sensor 1 — it was outside specification. Bank 1 Sensor 1 tested fine. I'm replacing both sensors with Denso models from Amazon. The truck has 150,000 miles and runs well but I can feel a slight misfire under load.

Anonymous 2019-01-17 12:00

Update: I replaced both upstream O2 sensors last night. Today, the check engine light turned off completely — a significant improvement!

Anonymous 2019-01-22 13:49

The light came back on recently — now only showing P0300. I've installed new spark plugs. I'm planning to clean the fuel injectors next. The previous owner replaced one coil pack but not all of them. I’ve retrieved freeze frame data: - STFT1: -3.9 - LTFT1: 8.6 - STFT2: 3.1 - LTFT2: 7.8 Any suggestions on where to start? Likely the injectors need cleaning — especially given the persistent misfire code.