I have a 2000 Nissan Frontier Crew Cab v6. My truck has aroud 102,500. I have been having chech engine light problems for several months now. I have gotten to the point of complete frustration. My engine light came on about 5 months ago and I let it go for about 2 months and then I realized that I needed to get it fixed before I had to get emission testing. So I took it to my mechanic and He ran diagnostics. The codes that he pulled were the p0131, p0151 and p0325. He told me that replacing the two upstream o2 sensors (p0131 and p0151) would fix the problem. So they were replaced and the next day my light came on again. I took my truck back to my mechanic. and the same 3 codes showed up. He told me to take it to Nissan and have them flash the computer because he thought that I needed their code reader to clear the codes. A day later the engine light came back on, same codes. I was told by my mechanic that it wouldn't be the knock sensor that is causing the problem so I havent gotten that replaced. I dont know if anyone has experienced this problem with my year frontier. If anyone could give me advice I would appreciate it. Thanks.

 

check to make sure there is no water in the 02 sensor connectors. they had a service bulletin for frontiers and xterras about water in connectors causing check engine light. If I remember the repair called for all new sensors and to replace the harness.