2002 Nissan Pathfinder Diag Codes P0455, P1448 and rear mai

Did you get a reply to your question? What did you do? I have a 2002 QX4 with 67K miles on it and have the same codes. Goes in the shop on Friday. Over $1000 seems very steep.

Hello - I looked into the Diag Code issue further and found it was almost certainly caused because I didn't screw the gas cap on tightly enough during my last trip to the gas station. So, I tightened the gas cap and then borrowed a system diag code reader from a friend and reset the codes after tightening the cap. Interestingly enough the codes haven't been triggered again so I think we fixed the problem. If you are having the same code issue and noticed your gas cap wasn't tight (after you can hear it click at least once) you might try closing it and then resetting the codes to see if it fixes your problem as well.

Regarding the rear main differential - I haven't noticed that the car is leaking any oil and am simply putting off that fix as I don't believe it is necessary right now. Their suggestion that I get this fixed because "most" cars with this amount of miles have the issue isn't enough for me to spend that kind of money on the car.

Cool. Good for you. I did try what you suggested and reset the code. Within 25 miles I got the code again. I pulled the lines off the canister and didn't notice any charcoal particles. Checked all the lines and they seem ok. I did purchase a new gas cap and put that on. Then I reset the code. So, we'll see what happens. I do have an appointment Friday to get the oil changed and have it checked. I have a small trip (100 miles)planned between now and Friday. Hopefully, I get the same luck you had. I did purchase an extended warranty, so maybe that will cover some of it. Maybe. Thanks for the info. I'll post how I make out

Well, I have had my QX4 in twice and am taking it back again this week for the third time. Here's what has been done: a new gas cap, new charcoal canister, and 2 new valves of some type. Both times they said it was repaired, but after less than 50 miles the code appeared again. So, I'm taking it back this week for the third time in as many weeks. Fortunately, my extended warrany has covered all, but $100 of the $800 bill. Get this, the dealer wanted to charge me another $100 for the second time I took it back and the repair didn't fix it. I wouldn't pay it. I imagine they'll try and hit me with another $100 this week. Will keep you posted.

Well, this is like the Never Ending Story. Have had my QX4 back 2 more times for the same problem. They replaced a solenoid and then another valve. I got it back last week and have put 55 miles on it. So far, "knock on wood" no "Service Engine Soon" light. Maybe it's fixed. The additional parts were another $400 so the whole deal was $1200.I paid $1300 for the extended warranty. Thank goodness. So I'm only $200 in the hole. Could be $1200. Just thought I'd keep you posted.