2001 Pathfinder, codes P1110 P1135 P0171 P0174

[91Pathfinder97]

Hi,

I just purchased a 2001 Pathfinder, 4WD, manual transmission last week. It's great fun to drive and I really like it. I've found lots of great info on this site to help with some of the minor issues I've found with the car. I have no previous service records on this vehicle (just hit 102,000 miles). I'm not that great with car mechanics, but my son is and he will be helping me.

Here's my question. The service engine soon light came on and I went to Autozone and they hooked it up to the OBDII reader and found four codes: P1110, P1135, P0171, and P0174. Car runs fine, no problems with lugging or missing. I will have to get it through WA emissions testing fairly soon. Which of these code issues should I address first? From my internet searches it appears that I should (cheapest to costliest):

- Replace gas cap (although it looks like this has just been done - with an aftermarket one)
- Change air filter with one I get from the Nissan dealer (looks like someone recently replaced this also, likely aftermarket one)
- Get an oil/filter change using 10W40
- Use higher octane gas (I didn't know so I just put in the regular octane I've always used in all my other cars, only one tank so far)
- See if codes go off/reset codes to see if they come on again (just purchased my own sensor to hook up to my Android phone so I can do this). But this may mean I have to wait a while to get emission tested or OBDII will give "Not Ready" signal and I'll fail emissions even if the SES light is off
- Replace MAF sensor with Nissan Maxima MAF part 22680-2Y001 (get from dealer) to address P0171 and P0174 codes
- Maybe replace fuel filter?
- Deal with P1110 and P1135 (still researching this one - kind of confused from what I've read)

Do these steps seem reasonable? Am I missing something? Has anyone ever had all of these codes at once or am I just lucky? Thanks for any advice!

[Chuck Tribolet]

Get a Wix oil filter, not a dealer filter. Get a Wix air filter while you are at it.

P1110 P1135 are the variable cam advance. 2001 PF has problems with that. It's powered by
oil pressure and as the truck gets older, the oil pressure goes down and the advance doesn't
advance as much, and the ECU notices and throws these codes. The 10W40 will help, and don't
give it full throttle between 1500 and 2500 RPM. I'm at 214,000 miles with 2001 stick PF, and
these codes have been coming and going for five years. If worse comes to worst, stick some
straight 50 weight in.

Don't worry about the fuel filter unless it has problems with full-throttle acceleration. It's
huge.

The fastest way to find out if the problem is fixed is to clear the codes. I'm pretty sure its
the same wait for the codes to clear naturally or for the manual clear to become OK to pass
smog.

Get the factory service manual.

Chuck

[Towncivilian]

I'd suggest switching to Mobil 1 High Mileage 10W-40 changed at 5,000 mile intervals to help clean any deposits up.

If you don't know when the fuel filter was last changed, it might be a good idea to change it out now and forget about it for 2 years or so.

What's the manufacturing date of your Pathfinder? It's on the driver door jamb sticker.

As for P0171 and P0174, also ensure there are no air intake leaks. Try running a bottle of Chevron Techron or Gumout Regane in a full gas tank to clean the fuel system.

Welcome to NICO!

[91Pathfinder97]

Manufacture date is 11/2000. Engine VQ35DE.

I ran Gumout through the first tank of gas to clean the fuel system, figured it couldn't hurt.

I took the Pathfinder in to my normal service station (been going there for 25 years) for an oil change and checkup. They ran some tests for the P0174 and P0171 codes. The MAF is failing the fuel trim test (notation says voltage and resistance test was fine). They recommended replacing the MAF sensor. So, dealer or online cost on the OEM Pathfinder MAF is around $400. Is the OEM Maxima MAF I've read about at $150 really a long-term viable option? I'm assuming that the cheap non-OEM Pathfinder MAF sensors you can find online are not a good idea.

Thanks for your help.

[Towncivilian]

You've got a 2001.5 model year Pathfinder. Download a copy of the factory service manual as it's an invaluable resource: http://www.nicoclub.com/FSM/pathfinder/ ... athfinder/
To save a copy of the FSM, right click -> Save As on every PDF, save them into a single folder, then use fwd.pdf to navigate.

I haven't read of anybody having the Maxima MAF fail down the road. It is an OEM part after all.

[91Pathfinder97]

Hi,

Well, I replaced the MAF sensor with the Maxima part, was a little tricky to get at that last bolt but my son had a small, long straight socket set that I used and finally got it. I checked it after a few short drives and all codes were still on, but and after driving it for a week or so (check engine light is still on), I checked the codes again today and the P0171 and P0174 codes are gone! The $100 Maxima part was much more cost effective than the $500 Pathfinder sensor, I'm so glad that these forums exist to help us newbies/non mechanical types.

I did get an oil change with the heavier weight oil and the P1110 and P1135 are still on (hence the check engine light), but I'll keep reading for what to do for those. Hopefully I can still pass emissions with those on.

I also figured out (from forums again) how to fix the clock by res-soldering the broken parts - and while I had the dashboard panel open I decided to install a 2-RCA to 3.5 mm stereo adapter onto the fancy non-stock stereo and ran it through a hidden hole I drilled in the panel to hook up my mp3 player (the stereo had extra AV inputs on the back for the DVD player). I was pretty excited that I did it all by myself, and it all seems to actually work.

Thanks again for your help!

[Towncivilian]

Great to hear you've solved some of your issues. Try 10W-30 first since it will generally be slightly thicker than a 5W-30 at operating temperature; if this does not resolve the codes within a few thousand miles, go ahead and try 10W-40.

[JMadd]

I just wanted to relate my experience with these codes. I had the P1135 code and numerous posts suggested the cam position sensor (POS in the Nissan docs) and suggested swapping the two to confirm the diagnosis. I did that and the codes swapped along with the sensors. I thought Cool! I'll just replace them both and be done with it. I ordered the Beck Arnley replacements. I put them in, threw away the old ones (big mistake). I didn't have a tool to clear the codes so I started patiently driving waiting for the check engine light to go off. It never did. When I went to the parts store and had them read the codes I now had more codes than what I started with. I believe it was the P1110 (that one was new) and P1135 and P1134. Crap! I ran through a jillion tests of the various other components as noted in various posts about these codes. No joy.

After a couple weeks of that I took it into a Nissan specialist shop that I've always had good luck with. It took them three days but they finally diagnosed it as *two* bad sensors - the same two new ones I'd just installed. They said at least one other time they had to go through three of the POS sensors to get a good one.

They also said you should *NOT* go to a 10-40 or higher viscosity. Stay with the 5-30 because of the tight tolerances in the engines required the lower viscosity or it could cause other sensor issues. I know that is not the common recommendation on this problem but I trust these guys to know what they are talking about they've been specializing in Nissans for 20 plus years.

That disabused me of my fixed idea about motor oils. Thirty years ago I had a mechanic tell me "Don't worry about multi-vis oils. This is Texas. Straight 30 weight!" I took that to mean keep the oil high viscosity unless you have to worry about cold weather. Not true anymore.

Anyway, the two new sensors fixed the problem. It's been two weeks now. Your experience may vary!
John

[Towncivilian]

While it is generally recommended to stick with the specified 5W-30, the factory service manual and even owner's manual states that 10W-30 and 10W-40 SAE oil grades are usable in certain temperature ranges.

Thanks for sharing your experience regarding the two bad sensors! That's an unfortunate circumstance for sure, but at least you were able to solve it.

[91Pathfinder97]

Thanks for the info about the sensors and oil. John, I'm glad you found the solution for yours. If you get a chance, please post future update if anything changes.

I've also taken my Pathfinder to a specialist; they tested and said: "PCM, cam sensors, and related wiring test good at this time. Issue is likely the cam adjusters. Recommend hot oil flush, drive for approximately 2 weeks and then schedule for further diagnostics." So I got the hot oil flush. They had cleared the codes. I drove 7 miles and the check engine light came back on; I checked and same P1110 and P1135 codes were listed again. I asked them and they said it could be quite expensive to continue trying to diagnose/fix things to see if it helped. So now I'm just driving it (it's my second car, not much mileage) and ignoring the light and waiting until I have a few thousand saved up and then maybe I'll take it back in for further diagnostics.

Other than the codes, I really love the car, it's in good shape otherwise, does well off road when I need it for my job and is fun to drive (OK, I'm comparing it to my other car which is an older minivan so almost anything would be more fun to drive.........)

[Chuck Tribolet]

I don't see where you've tried the thicker oil. It does help. See my post below.

Chuck

[JMadd]

Just a quick update. Its several weeks now since the new sensors and still no codes. I haven't changed the oil back, still running with the 10-40.