P0021 nightmare - pathfinder 2012

[Larockdog1]

Hello,
I have been chasing this code for a year now. I have replaced
Intake Valve Timing Control Solenoid Valve, crank position sensor.

For the past 6 months I did an engine flush to see if particle were blocking the solenoid and that seems to hold. After every oil change it comes back and I clear the code and it is good again.

Main issue I get is rough idle and sometimes drops down below 600 and then bounces back up. If in park I don't have the rough idle and driving around everything seems good.

A shop has quoted $4200 to replace sensors inside the engine and replace timing chain. Seems like maybe worst case scenario.

Hope someone here has had something similar or better advice.

[VStar650CL]

VQ40's of any year can get leaks in the gaskets or o-rings for the timing cover which supply oil to the cam phasers and solenoids. Unfortunately the shop is probably right, and it would be foolish not to do a timing kit while the front cover is off.

[Larockdog1]

Thank you! That's a Bummer. Would that be why it is so intermittent?

Is there a good way to test for that to see if gaskets are leaking. Oil pressure test maybe?

Could there be something else to check before going down the timing chain and gasket route?

Also is that something you would just drive untill I get worse performance? Just trying to stretch out the large cost if possible.

[VStar650CL]

It won't hurt anything to drive it that way as long as it doesn't blow out to the point where idle oil pressure drops off. The minimum is around 14 psi at warm idle, if you see pressure dropping below that then it's time for repair.

[Larockdog1]

What is the best way to test this?
Is this what a shop would test for me?

Any thoughts as to why it tends to go away and then come back after an oil change. Oil dirty and not escaping through gaskets.

Is this a common issue with this engine. I have about 107,000. Would you fix this.

[VStar650CL]

Oil viscosity changes with use. Usually it thickens unless there's fuel contamination or a bad PCV, because the lighter elements get boiled and combusted away. The passages in and out of the timing cover are very tiny, so it doesn't take much reduction in pressure to affect operation of the phasers. You might try going to 10W30 instead of the factory 5W30, that should help (just don't go thicker than that or you may get codes for the other cam).

I notice you changed the solenoid but not the sensor. Before you do anything else, I'd try that. CMP sensors can do some strange stuff when they go bad, and "missed teeth" can be the least of it. I once saw one reading 20+ degrees off true for absolutely no discernible reason, and because the signal was there but "late", the ECM was blaming the solenoid.

[Larockdog1]

First thank you for your help I really appreciate it!

Sorry I did replace the crank shaft position sensor and both camshaft sensor. They were aftermarket.

Should I replace with OEM?

[VStar650CL]

Depends what brand they were. Denso, NTK and Hitachi are all fine (provided they aren't counterfeit). If they're China-cheap, I'd suggest trying OE (or one of the above from a reputable vendor) just on bank2, since that's the only one throwing a code.

[Larockdog1]

Maybe I will replace. They are Import Direct. Not sure they are good or not. Says made in Mexico. I suppose it could also be a bad one.

Do I need to reset the computer or do anything after installing the new sensor.

The other odd thing is I replaced the VVT and then I had a shop check it because it gave the error again and they said that one was bad and not opening so replaced it again.

On a side note:
I have a clicking on the cylinder that attaches to the accelerator pedal. Almost like a servo? It even clicks when ignition is off for a while. Is this totally unrelated or could this also have something to do with the idle? Just thinking since it is attached to accelerator.

[PalmerWMD]

My 2 cents, I've bought off brand sensors before and they were bad out of the box twice in a row.
Only evident after install.
Like VStar ( our primary subject matter Expert) said, stick with those 3 name brands or Nissan direct only.

[VStar650CL]

Do I need to reset the computer or do anything after installing the new sensor.

No, it's plug and play (just a PITA to get at for replacement).

The other odd thing is I replaced the VVT and then I had a shop check it because it gave the error again and they said that one was bad and not opening so replaced it again.

I'm not sure how they would have checked that in the engine, but it is easy enough to check them when removed. Just put 12V across the terminals and you can hear and see the plunger move. I'd presume that's what they did.

On a side note: I have a clicking on the cylinder that attaches to the accelerator pedal. Almost like a servo? It even clicks when ignition is off for a while. Is this totally unrelated or could this also have something to do with the idle? Just thinking since it is attached to accelerator.

I don't have an R51 here to look at, but the APP assemblies are unitized and I don't recall them having an external damper. Maybe you mean the actuator for the memory seat pedal positioner? If so, a little low-level clicking or humming is normal when it operates, and if it's jammed or faulty it will keep trying to "return to zero" periodically. The APP itself is "dual slope" so as to be voltage-compensated and self-checking, and you'd be seeing P2122, P2127, P2138 or something along those lines if it had an issue. So it may have a positioning problem, but not a functional one that would relate to your engine code.

[Larockdog1]

Thank you I think I will just get a new sensor and just replace it and see if that helps.


As for the pedal assembly that sounds about right. It does a constant clicking.
I tried to attach file but would not let me. Here is a link to it.

Do you have to replace the whole pedal assembly? And is this just an annoying thing or if it fails would it be a safety thing.

https://res.cloudinary.com/us-auto-part ... siaps232_1

[VStar650CL]

Just an annoyance. Been a long time since I changed one, but my recollection is that it was a whole assembly and not very easy to get. If it's the one I think, the p/n is 18002-EA010 and NissanPartsDeal shows it discontinued.

[VStar650CL]

PS - If you dont want to fix it then there's nothing wrong with pulling or clipping the motor wires. If you do want to fix it and can't find the part, it's very likely you can take some measurements and find a replacement motor from a hobby store that will fit with some modifications. I found a photo, it looks to me like a sealed unit but if you find there are screws to disassemble it, it's also possible to measure and replace the brushes from an outfit like Eurton Electric. Eurton also does repair and I've found their website and customer service very helpful in locating replacements for extinct motors and motor hardware.

[VStar650CL]

PPS - I should also mention there's a cable connecting the accelerator pedal to the brake pedal so they can move together. If the cable fails it can jam the unit. Try popping the cable loose and see if suddenly the gas pedal moves with the switch the way it should. If so, the cable is the culprit.

[Larockdog1]

I unplugged and nothing changed so after further investigation and sticking my head under there it looks like it/sounds like it is come from up further. Looks like it might be a part attached to a white disc or fan looking thing. Might be a servo attached to the climate control stuff. I know the reciculated air button dosent work and sometimes changing the modes don't work always.

I think I read that it is a blend door actuator.

[VStar650CL]

That will be one of the HVAC servos, yes. Same deal, if they can't find their zero position they keep trying over and over. Very common on gen1 Titans and Armadas, less common in Pathies but it does happen.

[Larockdog1]

Thank you for your help I will report back. New sensor was installed so fingers crossed.

Can the idle not in park be adjusted or is it all computer based. The dealer adjusted it after I replaced the VVT but it seems so low. I could pull live data but I think it is below 600.
Does that seem right or can I have it adjusted up a bit?

[VStar650CL]

It's computer-based on a '12. There is a provision for raising or lowering the "target speed", but tinkering with it isn't a great idea for reasons that would take some major explaining. It's possible the dealer didn't warm it up fully when doing the IAVL, the ECM will let you do it at 70C but in my experience you really want to get them above 80C or they can be cranky.

[Larockdog1]

Light came on and same code again.

I guess next step is the dealer? And other thoughts. I guess next step is to pay for a full diagnosis at dealer.

[VStar650CL]

With a new IVT, a new sensor, and a flush, oil pressure or flow is pretty much all that's left. Like I said back at the top, unfortunately the shop that quoted you a cover and chains is probably right.

[Larockdog1]

Do you think it is best to go to the dealer for this or can other shops work this issue.
My only concern is if they have experience with this vehicle or have the right equipment to diagnose?

[VStar650CL]

Most busy shops have done VQ chains at some point and it isn't exactly rocket science, but it isn't a newbie job either. If there's a shop that's done a few and you trust their work, I'd say there's nothing wrong with that.