Hi Guys,

My wife has a 2002 Pathfinder and I just got a call from her on Friday night saying that the car started running rough and the Service Engine Soon (SES) light was flashing. She had pulled over immediately and I came out to see what was going on.

When I got there I checked the oil and it was pretty dry. I added about 4 quarts of oil for it to show as a bit over the full mark on the dip stick. I started it up and it was idling a little rough (like it was missing on a cylinder) but the SES light wasn't flashing any more.

So I thought I'd drive it home. As soon as the car got up above about 35mph the SES light would start flashing again until I slowed down at which point it stopped flashing. Same happened at about 20mph up a bit of a hill.

I got home after the short drive (maybe 2 miles) and the car has just been sitting in the driveway since Friday night. I checked the oil today (Sunday) and it's still at the same High point on the dip stick.

I read in the Pathfinder manual that it could indicate a problem with the emission system but that it was safe to drive as long as you stayed under 45mph. The thing that has me concerned is that the oil was crazy low - so I'm hoping she hasn't done damage to the engine itself.

Any ideas what's going on? Should I have it towed to the mechanic? Thanks!

Did you notice any abnormal noises from the engine when you started it after refilling it with oil?
A blinking SES light typically means severe engine misfire. Out of curiosity, was the oil pressure light on when your wife first reported the issue?

Did you plug in an OBD II reader to check for codes?

No weird noises at all - and no to the oil pressure light either (but who knows - she could have missed it but she swears it didn't come on). When I drove it home, it did run a little rough but not crazy rough but I did keep the speed under 30 the whole way!

I'll plug the ODB II reader in now. Good thinking!!

Yeah post the codes back here.
My mom had an Olds Silhouette years ago that did the same thing (rapidly flashing SES, vibrating at speeds of 40mph and above, but no issues with the oil). In that specific case, all it needed was new plugs and 1 coil. Hopefully your fix is also relatively simple.

Ok here are the results of the ODB scan. Misfire on cycliner 3.



Whatcha think?

Was the light on before you had a problem .... in other world have you been driving it with the CEL light?

The O2 sensor heaters are a known failure point on the pathfinder -- it's because the car leaves the heaters on too long. Nissan has a firmware upgrade for the car .. but, unless the 02 sensors were replaced with the firmware they will have shorter life. Many O2 sensors have heaters to get them up to temp quickly ... O2's are only accurate when at temp.

A bad heater on the O2 will not cause any driving problems as the sensor part is still working -- it will turn on the CEL.

Whenever you see the CEL flashing -- you should not drive the car. This is true for any car. The flashing CEL is alerting you that the engine is missing enough that gasoline could be flowing unburned into the exhaust .. this will then ignite in the Cat converter -- overheating the converter. They can melt.

Driving an engine with only 1qt of oil is not good ... it could have been knocking and the engine was thinking it was missing. Who knows ... clear the codes and start it and see what code comes back first. If it comes back missing on #3 -- I would think the coil is bad. Switch the coil from another cylinder and see if the code travels to that Cyl. Replace the coil and pray to the oil gods .. then teach her how to check it (the oil)

How do I know which one is cylinder 3?

look on page 20

http://www.nicoclub.com/service-manual? ... hfinder/ma

OK so cylinder 3 is the middle one on the right side according to the manual. Does this mean the right side if I'm standing at the front of the car looking at the engine?

no right side is passenger side

Okay awesome - so that's the easier side to get to.

UPDATE: I cleared the engine codes this morning and the SES light turned off. It was idling fairly smoothly too - but I could tell it wasn't quite right! I drove around the neighborhood and as soon as I tried to accelerate a bit harder the SES light started flashing again. So retested and just got the one error code for the Cylinder 3 misfire (P0303).

I guess the next step is to change the engine coil from Cylinder 3 to another cylinder. Are all the engine coils the same? Since the passenger side cylinders are easier to get to, if it makes sense to do so, I might swap the coils from Cylinder 3 and 5 around and retest.

If the code does follow to Cylinder 5, then would I just need to replace the one coil, or should I replace all 6 coils at the same time?

Thanks so much for all your help!!

UPDATE: I pulled out the Ignition Coil on Cylinder 3 and am just going to go purchase a new one to put in there rather than moving the others around. I figured I could always take it back if it didn't end up being the coil!

So will grab one tomorrow from Autozone and read the codes and see what happens! Do I need to change out the spark plug as well, or just the coil?

At least pull the plug and inspect it for oil, carbon build up or erosion as that can cause the miss. Clean and reinstall. Good luck with the coil. We had a misfire, swapped the coil with another cylinder and has not been a problem since. Autozone may not take back electrical parts once they've been installed.

I didn't see the number of miles on the vehicle in your previous posts. You might want to change the plugs as well if they haven't been done during the factory specified schedule. They are supposed to changed every 105k miles with platinum plugs IIRC.

UPDATE: I swapped the Coil from Cyl 3 to 1 and started up the car. It idled just as roughly as before and when I drove it around it threw an Engine Misfire on Cylinder 1! So that was good news! I replaced the Cylinder 1 coil with the new one I had bought and bingo, idled smoothly and didn't throw and error codes on my quick drive around the neighborhood! Checked the oil and everything looked good!

I'll take it on a longer test drive this afternoon, but I'm confident this has sorted the issue. THANKS so much for all the help on this! Saved me a ton I'm sure!!!

That's great! Even greater, no dealer $$$ involved.

Yes exactly!! I didn't answer the question earlier but the SES light has been on for years because of the O2 sensor. It turned off after I reset it but came on again last night after driving around for a bit. The P0158 and P0037 codes came back on (see above image). Are these worth worrying about, or should I just keep living with it like I have for the last few years?

Those more than likely are o2 sensor malfunctions, or a problem with the catalyst. Id replace the downstream o2 sensors first before i start throwing money for the catalyst. if you replace one of the downstream (after the catalytic converters) o2 sensors and the corresponding bank 1 or 2 code disappears id replace the other 3. the upstream o2 sensors control fuel flow into the combustion chamber and would probably help with fuel mileage. My concern is if you replaced the oil within the past 3-5k miles you need to find out where that oil is going. if its leaking past the valve stem seals in the heads then your going to have a ton of carbon pankcakes in the combustion chamber increasing compression and robbing engine power. But my money is on the PCV valve in the back of the passenger side valve cover is clogged.

I was getting an O2 code for the passenger, downstream sensor. It took awhile after a reset to come back, so I expect the cat is marginal. For now I'm using a spacer to move the sensor out about an inch and no codes since. It's about $5 from Autozone and just few minutes to install, so was worth a try. As 850path suggested, I'll probably get around to trying a new sensor before I'd tackle replacing the cats but for now not worried about it.

https://www.youtube.com/watch?v=wcDPAfz10Io&t=6s

As I said above the pathfinders had a firmware upgrade to stop the heaters from running as long .. the one code is showing the heater circuit has failed. the other is showing the sensor has failed. Two of the sensors have heaters -- so 4 wire and two are only the sensors. The up stream sensors are used for engine management the down are to check the converters. the downstream don't need heaters as the heat from the converters is enough.

If you have emission inspections you will need to get them fixed. Amazon is often a good place to get them ... I would get direct fit .. they are not that easy to replace and the wires are very long and the placement difficult w/o a lift. You don't want the universal

NTK 24405 Passenger
NTK 24406 driver

OEM manufacturer and have worked great on my pathy after 7-8k miles

OK, so I had this happen tonight on my 2002 Pathy.
Started running rough, almost dying, and then the check engine light started flashing.
Flashed for maybe ten seconds, then went steady, then flashed again.
I wasn't far from home, so I drove it back, all the while the engine was misfiring.
I'm going to get a scanner tomorrow and check the codes, but in the meantime, here's my question: Are all the ignition coils the same?
If they are, I'll order one preemptively, and have one on hand for troubleshooting.
The bigger problem is the cold weather, the snow, and the fact that we are in a pandemic lockdown here in Ontario (Canada).
Nothing is open. I would have to order the part, do a curbside pickup, and hope it gets a little warmer.
Why couldn't this happen in July????? AArrgghh.

Haha exactly. Yes all the coils are the same and they’re fairly easy to replace. I had to remove the air intake to get to cylinder 4 which has been the most complicated so far! Good luck!

Hey, I'm just searching on line for coils, and I'm getting mixed messages re: OEM vs third party coils.
Checking some cheaper coils on Amazon results in some negative reviews. Looks like some brands are garbage.
Is it better just to bite the bullet and go OEM? I hate spending money on this truck as it is definitely on it's last legs.

I went with the cheaper ones and so far they have been fine. I bought extra just in case one failed - they are pretty easy to replace so it was worth the savings IMHO

All right, so I just pulled the codes: Main one is 0304, cyl 4 misfire.
Stupid question: which one is #4?

Ok, I just googled it. Looks like #4 is middle drivers' side. Correct?

Yep - and that's the tough one to replace. You have to remove the engine air intake manifold to get to the coil! It's not difficult, but just a bit more complicated! Good luck!

Of course it has to be the one under the air intake. Couldn't be number 1 now could it?...lol.
I've had that area all apart before, when I replaced my IACV and did my power valve screws, so it's not a biggie.
It's the freekin' weather that's the problem. It's -10C right now.
I'll keep you posted.
Thanks for your help btw. Appreciate it.

Hey no worries - yeah that's too cold to be working under the hood! Good luck!