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2000 Nissan Pathfinder 3.3L V6 - All Four O2 Sensor Heater Circuit Faults (Codes P0135, P0141, P0155, P0161)

Model: 2000 Pathfinder Fault Code: P2177 Posted: 2013-06-19 12:12

I own a 2000 Nissan Pathfinder with a 3.3L V6 engine. About a month ago, I took it to a repair shop where they replaced the valve cover gaskets, front axle components, and Bank 2 Sensor 2 O2 sensor. At that time, I was experiencing code PO161 (O2 sensor heater circuit malfunction). Since then, everything has been running fine—until today. Now I'm getting multiple O2 sensor heater fault codes: P0135, P0141, P0155, and P0161. These indicate a heater circuit issue for all four oxygen sensors. This is highly unusual—having all four O2 sensors show the same heater malfunction simultaneously. Are all four sensors connected to the same wiring harness? What should I check first? I've cleared the codes, but they return every time I start the engine. Any insight into possible causes or diagnostic steps would be greatly appreciated.

Related fault codes
P2177
Comments (3)
Anonymous 2013-06-19 13:21

DTC P0135 (Right Bank - B1), P0155 (Left Bank - B2) — Front O2 sensor heater circuits DTC P0141 (Right Bank - B1), P0161 (Left Bank - B2) — Rear O2 sensor heater circuits It's indeed unusual for all four sensors to fail simultaneously. Let's start by checking the common 12V power supply to the heaters. With the engine off (KOEO), test the black/white wire at each O2 sensor probe for 12V power—does it show voltage? This 12V typically comes from the fuse box, specifically a 10-amp fuse labeled #25. Check that first before moving on.

Anonymous 2013-06-20 09:27

Thank you so much for your prompt and accurate guidance, Kev2. I checked the fuses first—this was the simplest step—and found that the 10-amp fuse #25 in the fuse box was blown. I replaced it, cleared the fault codes, restarted the engine, and all systems are now functioning normally. If the issue returns, I'll need to investigate further—but your advice saved me from a lot of guesswork and unnecessary repairs. Truly appreciate it!

Anonymous 2013-06-20 10:56

If the O2 sensor replacement was not an original Nissan OEM part, that could be a potential cause—non-OEM sensors may have faulty heater circuits or poor wiring connections.