Pathfinder power loss, DTC code

nissan
sensors
#1

98 Pathfinder 2wD, 3.3 V6, Manual transmission. 178k miles.



Problem:

I’ve been experiencing a noticeable loss of power. This started out as an intermittent problem, especially during hard acceleration on the interstate, and when pulling the boat. This has been going on for months, but has recently worsened. It seems to happen more when it has been sitting out in the hot sun all day before driving home from work.



The “service engine soon” light is on, the code given is for the Crank Position Circuit, I forget the actual code number. I have no idea if this is related to my problem, because the light has been on (with the same code, I checked it occasionally) for the 5 or so years I’ve had the truck. Never had had any engine problems, other than the recalled exhaust manifold.



Hypothesis:

1.At first I thought it could be the clutch starting to slip. But the engine doesn’t rev when it loses power, the tach stays still.



2.Air filter? I changed it at the last oil change, no difference.



3.My next guess is the fuel filter, which to my knowledge has never been touched. I think this because my old 85 Nissan truck would act similar because I had rust in the gas tank, and the filter would clog if the fuel got too low.



any Ideas?



thanks in advance!

#2

SES on for 5 years?!?!?! Oh well, I guess that isn’t important until your left stranded on the side of the road. Please get the actual code and post it here. We can help if we had the actual code.

Never changed the fuel filter? Please read the owner’s manual. Most modern EFI systems request a fuel filter change every 60K to 90K. Your way overdue.

Anything else neglected? Look over the recommended service schedule in the owner’s manual and any service records or memory. Check off what was done, and if it was done on time. If you missed something, like fluid changes or filter replacements, now is the time to catch up.

1 Like
#3

Accelerating and after a while you start to loose power…sounds like fuel starvation to me. I’d replace the fuel filter fast. It’s located above the rear axle. Not easy to get at, but not impossible.

I really suggest you keep up on the maintanance. This is going to cost you a lot more fixing problems that arrise because of poor maintenance.

#4

PO335 Crankshaft Position Circuit Malfunction

Yea I know it’s pretty horrible to leave a light on like that. But let me just say, the thing ran perfect up until now.

I do pretty good with regular maintenance, but I didn’t have the owners manual until recently I found a pdf online. I will go through the maintenance schedule now.

#5

going through the owners manual maintenance schedule, there is no regularly scheduled fuel filter change. However, it has a footnote:

“If vehicle is operated under extremely adverse weather conditions or in areas where ambient temperatures are either extremely low or
extremely high, the filters might become clogged. In such an event, replace them immediately.”

with this high mileage, and Alabama Summer in full effect, all signs point to fuel filter.

#6

Thanks, I’ll try that next

#7

Ok I’ve been chasing this problem down for a while now, thought I’d report in and let you know what’s been going on.

New fuel filter didn’t help.
I put new plugs and wires on yesterday, that didn’t help.
Today i replaced the distributor cap and rotor button, and on the test drive, I didn’t notice any power loss. So maybe that fixed it, but I doubt it. All those parts needed to be replaced anyway.

I’m looking for the crank position sensor now. “The internet” says its on the back of the motor, in the bell housing but I have yet to see it.

I’ll let you all know how that goes.

#8

One thing to consider is that you hadn’t changed the fuel filter for years. Fuel injectors really don’t like dirt. There’s a good chance there’s dirt there. Try a couple of cans of Chevron Techron or Seafoam for a few tanks of gas and see if that clears it out.

#9

Did you erase the DTC code for the crankshaft position sensor? Disconnecting the battery for 5 minuets may do it, if you don’t erase it with a scan tool. Then, drive it and see if the light comes back.
You could test the output voltage of the crankshaft position sensor at the engine computer (ECM), with the engine running. Here are the desired dc voltage values: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280027c5e You could backprobe the ECM terminal 47 (blue wire), and use a high impedance multimeter to take the dc volt measurements. There are 4 blue wires on the ECM: 44, 47, 48, and 76. To box in those wires, they are between ECM 45 green/white, and ECM 49 black/white.
Look for the crankshaft position sensor from under the car. These drawings show it a few inches from an oxygen sensor, mounted on the transmission: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528001b960
Furthermore, the fuel pump may have become weak. You need to check its pressure output, and check the fuel pressure regulator.

#10

Update!

Thanks everyone for your replies, here’s an update:

Found the sensor, that thing is a bastard to get to!

It seems that the previous owner had problems with this sensor too. The clip that keeps the plug from backing out was broken, and the wires just fell out of the back of the plug!

Turns out, the last guy must have yanked the wires out when he broke the plug, and “fixed” it by taping two pieces of heavy solid copper wire to the ends of the wire, and jamming them into the plug with more electrical tape.

So now I’m hunting for a piece of wiring harness so I can fix the plug. Soldiering and shrink tubing will be used of course.

And the sensor itself tested bad. According to my Haynes Manual, it should give about 530-650 Ohms resistance, it showed around 190 ohms.

Does anyone know where I can find this plug? I’m hesitant to go to the junk yard, but I will, if I have to.

UPDATE UPDATE

Found the plug at the junk yard this morning. It wasn’t that bad, this place will still let you walk around all the cars and help yourself to what you need.

I got two plugs that will work, just to be safe. Both came from late 90s Altimas.

Ordered the sensor today, I’ll get it tomorrow.

#11

I have cleared the code a few times, it always comes back.

I will check the fuel pump, if this crank position sensor doesn’t fix it.

#12

Yea, it’d probably be a good idea to do that anyway, acceleration problem or not.

#13

Yea I know it’s pretty horrible to leave a light on like that. But let me just say, the thing ran perfect up until now.

I and glad to read that you apparently have found the answer to your problem.

I have to suggest that just because a car runs well is no reason to ignore that CEL light. Keep in mind that that light can come on due to a problem that is not yet causing any noticeable problems, but could cause some very expensive damage, maybe even make the car unsafe. (Note a blinking CEL light means STOP NOW.) Driving with a light on also hides any new problems that might come up. In short it is very short sighted to ignore that light.

#14

Great! The power of visual inspection and testing can help find fault causes that other methods may not (at least, quickly) find. Congrats!
You can get electrical connector repair kits from the dealer, but, it won’t be cheap. You don’t really want to think about changing the crankshaft position sensor wiring harness.
You can repair the wires with an individual wire connectors, which can be disconnected just by pulling them apart. Check at Radio Shack.