Nissan Forum banner
1 - 20 of 42 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter · #1 ·
Hello,

I am looking at a 2001 Nissan Pathfinder 4x4 (AUTO) with relatively low miles. It has 140,000 original miles and is agreat looking car!

However, the small town dealership (two man show, unaffiliated with Nissan) said it has a SES light on. The code is P1140 (camshaft position sensor). He replaced the bad sensors and it’s still throwing the same code. I test drove it today and it drives like a dream! Doesnt stall at lights, doesn’t hesitate at any RPM and overall runs great. The previous owner lived in a non emissions county (NC) and was also never able to get the SES light to go off. On Jan 1st 2021 the car is emissions exempt in NC and will be available for sale. While I was test driving the car the SES light went off. I then parked the car and walked into the shop to return the key but realized I forgot to test the 4x4 functionality. I got back in the truck and as soon as I fired it up the light was back on.

I don’t like riding around with SES lights on. I’d rather find the root of the problem, but can’t seem to find a forum with a likely fix. Has anyone had this same issue with a 1999-2004 Pathfinder where the engine runs smooth as silk, but has pesky codes that will not clear after parts are thrown at it? Since the car runs good is it a good purchase? Will it last even though the SES light is on?
 

·
Registered
Joined
·
19 Posts
I had a 2004 Nissan Pathfinder that threw camshaft position sensor codes. I replaced camshaft position sensors (throwing parts at it). When it didnt help I took it to Nissan Dealer. They told me that very dirty or low oil levels will cause this and it is very common with these years. They changed the oil and the Service Engine light went away. Since then I have been a little more attentive to oil change/levels. Btw...these pathfinders lose oil somewhere. No smoke from tailpipe, no dark soot or oily tailpipe. No drips on driveway or obvious oil leaks. Just gotta keep feeding oil.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #3 ·
I’ve read where some people will do an oil flush. Does that seem to help? I am meticulous with my oil changes and typically run full synthetic in my vehicles and change it no later than 3500 miles or 4 months. I’ll be sure to keep oil in it and I check it every 2 weeks or so.

As far as this pathfinder is concerned should the SES light be a dealbreaker? I’m talking it to be evaluated tomorrow by a mechanic friend. Like I said, it runs like new and all systems function as the should. I ran it to the redline with the salesman’s permission. Everything checks out on the car except the SES.
 

·
Banned
2003 Nissan frontier XE D22
Joined
·
112 Posts
If its a Vg engine. It might be a faulty MAF sensor. If its the vq engine, you might want to clean the tooth on the camshaft sensor reluctor wheel.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #5 ·
If its a Vg engine. It might be a faulty MAF sensor. If its the vq engine, you might want to clean the tooth on the camshaft sensor reluctor wheel.
If its a Vg engine. It might be a faulty MAF sensor. If its the vq engine, you might want to clean the tooth on the camshaft sensor reluctor wheel.
How can I tell the difference between engines? (VG/VQ)
 

·
Banned
2003 Nissan frontier XE D22
Joined
·
112 Posts
O.k. the VQ35DE is dual overhead camshaft v6 engine. While the VG33E is a single over head camshaft. The vq is 280hp . the vg is 180hp.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #7 ·
If its a Vg engine. It might be a faulty MAF sensor. If its the vq engine, you might want to clean the tooth on the camshaft sensor reluctor wheel.
I believe it’s a VG engine. It’s a 2001 Pathfinder LE. It’s a 3.5L engine.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #8 ·
O.k. the VQ35DE is dual overhead camshaft v6 engine. While the VG33E is a single over head camshaft. The vq is 280hp . the vg is 180hp.
Just thought of this. When I test drove the car I drove it about 8 miles or so. The SES light went off during my drive. When I got back to the lot I shut the car off and restarted it and the SES was back. Any idea why the car would do that? Intermittent??
 

·
Registered
Joined
·
1,438 Posts
If you're sure it's 3.5L then it's a VQ. Steve is right about cleaning the reluctor wheels, little bits of magnetized junk can stick to them and false-trigger the sensors, making the ECM think the timing is off. That happens a lot on older motors. Because it's old, you should also check the integrity of the engine grounds, not just the main cable but also the two 10mm rings underneath the front of the engine cover. One of those will be the block ground for both CMP sensors. Again because it's old, it's possible you have bad pin-fit on either a sensor connector or an ECM connector. Broken or weak tension springs in the female pins can cause all sorts of invisible -- and usually intermittent -- issues. Lastly, we've seen a few cases over the years where a weak crank sensor that was missing occasional teeth made the ECM throw incorrect CMP codes. We're not privy to the code Hitachi writes for ECM's, but it appears to us that a false "index gap" from a weak sensor can make the ECM incorrectly decide that the cams are off.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #10 ·
VStar,

Thanks so much for that. The lot the car is at told me that they would let me take it home for the day (tomorrow, December 19th, 2020). Im going to take it to a mechanic and have him help me.

I’ve got a few troubleshooting things I’m planning on doing with my mechanic’s friends help. I’ll definitely try taking them out and cleaning them too!!

The guy told me he replaced the VCT solenoids which is what I thought the P1140 code was. Since he replaced those parts is it likely sensors now?

Also, it’s worth restating that the car runs like a dream. How is the drivability with the code (p1140)?
 

·
Registered
Joined
·
1,438 Posts
I've never seen a Nissan ECM confuse a bad CMP for a different issue. If there's a hydraulic or electrical issue like a blocked oil passage, bad phaser or bad IVT, you won't get a P1140. To verify if it's the sensor causing the problem or something else in the circuit, you can try swapping the Bank1 and Bank2 sensors (they're identical part numbers). If the problem moves (P1145 I think) then the sensor is faulty, if it doesn't move then the cause is one of the other issues. People often use cheap China-clone parts and usually they work okay, but it wouldn't be the first time I've seen a crappy CMP or CKP out of the box. People drop them, too, and then reinstall them. If Hall sensors are dropped on a hard surface and then re-used, you're asking for trouble. The impact almost always de-magnetizes them to some degree. So a simple bad replacement part isn't out of the question.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #12 ·
VStar,

I hope it’s something simple like that too. Are there any other codes that accompany a P1140 I need to be prepared for? Are there codes that, if present, are a dealbreaker? The guy just told me the p1140 code is shown, but I reckon there could be more. I plan to swap the sensors and see what happens. Hell, I might put one on the truck and fix it if the parts house has some on hand.

My mechanic friend has a mid-tier scan tool so he will be able to see more from the ECU. It’s certainly reassuring to hear that the ECU doesn’t mistakingly label bad phasers, IVT, ect. as p1140 often.

I’m hoping it’s an easy fix because this Pathfinder has relatively low miles and is priced at market value which is significantly below my budget. I was looking at 05-12 Pathfinders, but this ones interior and condition caught my eye.
 

·
Registered
Joined
·
1,438 Posts
If there are any IVT codes along with the P1140 then there's probably something wrong in the oil system, since the IVT solenoid is also new. The whole IVT system runs on oil pressure, both the solenoid and phasers, but since only one bank is throwing codes, it won't be a global pressure problem. If you find any other codes, I'll help you translate.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #14 ·
Gotcha. Thanks so much for your help. It’s helped me clear up a lot of random thoughts.

P1140 is the only code I know of. It’s the only one he’s told me about. I assume there could be more codes. In my experience with Fords I’ve always had 2-5 codes thrown with one issue. Could he different though.

I’m “borrowing” the car from the dealership to have my mechanic inspect it tomorrow. I’ll update the forum once I learn more about the codes stored.

Again, thanks for your help!
 

·
Admin and Sup Mod keeping the peace
Joined
·
7,728 Posts
I believe it’s a VG engine. It’s a 2001 Pathfinder LE. It’s a 3.5L engine.
Starting in 2001 Nissan used the VQ35DE 3.5L engine in the Pathfinder.
P1140 is the only code I know of. It’s the only one he’s told me about. I assume there could be more codes. In my experience with Fords I’ve always had 2-5 codes thrown with one issue. Could he different though.
The P1140 code indicates that a malfunction is detected when an excessively high or low voltage from the sensor on Bank 1 (right side) is sent to the ECM. The possible cause could be a bad harness connector, oxidation on the pins, open or shorted wires or the sensor itself is bad. As suggested previously, you can swap the sensors between bank 1 and 2; if the code is now P1145, then that sensor is bad.

You can also test the voltage output with a multimeter instead of using an oscilloscope. With the engine warmed up and running, the reading should be approximately 0.5V. Test between Y/G wire (pin 2) on the sensor and chassis ground. (CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM’s transistor. Use a ground other than the ECM terminals, such as the chassis ground.)
 

·
Registered
Joined
·
1,438 Posts
The P1140 code indicates that a malfunction is detected when an excessively high or low voltage from the sensor on Bank 1 (right side) is sent to the ECM.
Yep, P1140 is basically a "flatline" code, as opposed to an "irrationality" or "performance" code. Flatline means the ECM didn't see one or more high-low transitions where it was supposed to see them, so it flags the sensor as "stuck high" or "stuck low". Pretty straightforward, which is why I don't suspect you'll find other related codes unless there's a hydraulic issue.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #17 ·
VStar and Rogoman,

My mechanic looked at the Pathfinder today. He inspected basically everything on the vehicle and it checked out. As far as the SES light, we found that the code jumped (p1145). There was also an o2 sensor code (which doesnt matter after 2021 as it will be emissions exempt in NC). Diagnosed as a bad sensor. I bought the Pathfinder from the lot for $2,800 out the door. My mechanic’s personal top dollar was $3,500. It still stumps me as to how the car runs so well even with the bad cam sensor. No vibrating, no stalling, no rough starts (warm and cold), or high idle.

The guy at the lot said he replaced both VCT solenoids and flushed the oil 3 times thinking that would clear the code. He never replaced the cam sensor.

While inspecting the Pathfinder my mechanic found that the power steering rack is leaking. He’s going to replace it for me (~400-600 dollar job). It’s also missing a skid plate for the front. My best guess is a DIY person didnt put it back on. I’ll get one front a junkyard.

Overall I’m excited! I feel like I got a pretty good deal. My mechanic also reassured me by pricing how much he could get a replacement motor for. $600 is his price for a motor with <60k miles. He said installed he could have it installed for less than $1,000 grand total.
 

·
Admin and Sup Mod keeping the peace
Joined
·
7,728 Posts
VStar and Rogoman,

My mechanic looked at the Pathfinder today. He inspected basically everything on the vehicle and it checked out. As far as the SES light, we found that the code jumped (p1145). There was also an o2 sensor code (which doesnt matter after 2021 as it will be emissions exempt in NC). Diagnosed as a bad sensor. I bought the Pathfinder from the lot for $2,800 out the door. My mechanic’s personal top dollar was $3,500. It still stumps me as to how the car runs so well even with the bad cam sensor. No vibrating, no stalling, no rough starts (warm and cold), or high idle.

The guy at the lot said he replaced both VCT solenoids and flushed the oil 3 times thinking that would clear the code. He never replaced the cam sensor.

While inspecting the Pathfinder my mechanic found that the power steering rack is leaking. He’s going to replace it for me (~400-600 dollar job). It’s also missing a skid plate for the front. My best guess is a DIY person didnt put it back on. I’ll get one front a junkyard.

Overall I’m excited! I feel like I got a pretty good deal. My mechanic also reassured me by pricing how much he could get a replacement motor for. $600 is his price for a motor with <60k miles. He said installed he could have it installed for less than $1,000 grand total.
Glad that it all worked out OK.
 

·
Registered
Joined
·
1,438 Posts
Good to hear! Yah, if it moved then the diagnosis is absolute, the sensor is shot. It probably isn't affecting the way the car runs because it isn't dead yet, just weak and missing occasional signal edges.

I'd get the HO2S fixed anyhow, given the car's age. The rear sensor is "for the government" in the sense that its job is to make sure the catalyst is working, but that doesn't mean you should forget about it. It will also warn you if a cat is going south, and you definitely want that. Disintegrating cats are probably the number one cause of destroyed Nissan engines. Most don't have EGR and instead manipulate the IVT system to breathe back a bit of exhaust into the combustion chamber on the intake stroke. That works great unless a cat disintegrates and the engine inhales metal dust. Then it's goodbye piston rings and off to the junkyard for a used engine.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #20 ·
Good to hear! Yah, if it moved then the diagnosis is absolute, the sensor is shot. It probably isn't affecting the way the car runs because it isn't dead yet, just weak and missing occasional signal edges.

I'd get the HO2S fixed anyhow, given the car's age. The rear sensor is "for the government" in the sense that its job is to make sure the catalyst is working, but that doesn't mean you should forget about it. It will also warn you if a cat is going south, and you definitely want that. Disintegrating cats are probably the number one cause of destroyed Nissan engines. Most don't have EGR and instead manipulate the IVT system to breathe back a bit of exhaust into the combustion chamber on the intake stroke. That works great unless a cat disintegrates and the engine inhales metal dust. Then it's goodbye piston rings and off to the junkyard for a used engine.
VStar,

Yeah since I got a deal on the car I’m definitely planning on fixing the O2 sensor. It’s going to be a bit of a project for a while, but I got it for $4,000 less than I was willing to spend on a Pathfinder/XTerra.

Quick question: Which Camshaft sensors do I need to replace? With the P1140 I believe it is the intake cam sensor. It’s a bit confusing because some refer to it as “VCT sensor” (or something similar). I am planning on replacing all sensors including the crank sensors for good measure. Do you know the part numbers? I’ve read a lot of forums where people have issues with buying the wrong ones for the code they have. That’s mainly why I plan to replace all of them.

Also, do you have a good graphic with the location of the sensors or a video of someone replacing the sensors? It’s a bit hard to diagnose this stuff when the car isn’t yet in my garage.

Thanks so much for your help!
 
1 - 20 of 42 Posts
Top