P0160 O2 Sensor Fault Diagnosis - 1996 GMC 3500 5.7L Diesel / Gasoline (Bank 2 Downstream Sensor 2)
Hello, I'm a 77-year-old gearhead with tools and some mechanical experience — but I'm stuck on a recurring O2 sensor issue. The P0160 code has appeared despite replacing the oxygen sensor twice and installing a new MAF sensor. Voltage checks confirm proper 12V supply and good ground at the sensor. I've consulted three mechanics and two smog shops across five different locations — each spent several hours troubleshooting with no resolution. The truck runs smoothly, maintains excellent fuel economy, and delivers strong performance. My smog check was due last August, so I need a reliable fix before that expires. Any insight into diagnosing this P0160 code on my 1996 GMC 3500 5.7L engine would be greatly appreciated. Thank you, Tom
Are you still having trouble with the P0160 code on your 1996 GMC 3500 5.7L? Please confirm if you've checked for exhaust leaks and specify which model variant (e.g., diesel or gasoline) you have, as this affects sensor behavior. The P0160 code refers to the downstream oxygen sensor on Bank 2 (passenger side), Sensor 2 — located after the muffler. If possible, use a test light to verify connections. While crawling under the truck may not be ideal for everyone, I recommend inspecting the O2 sensor connector for corrosion or green crust, especially at the contact points. This is typically a 4-wire harness. Note: The truck's wiring harness side has female receptacles that accept male pins from the sensor — check these gaps carefully to ensure they're not visibly enlarged or damaged. David Edit: I apologize if this sounds technical — I'm just trying to assess your experience level and provide actionable steps.