First post here. Hope I can contribute some day, but for now I'm just a forum "user" . I'm in San Diego.

Just got a nice condition, original female owner, 03 LE 4x4 for my son with 119k miles for $3500. She had every receipt since new. This was the 5th we'd looked at and needed none of the common suspension work that most seen to need. The only issue at purchase was a RMS leak (more on this below) that we negotiated the price down to include $600 repair.

Her recent repair receipt was for the P0021, for which she had the solenoids and one sensor replaced plus oil change ($1300 at dealer!). Here's the progression after our purchase -

Picked up truck, >100 miles from home. Before driving home wiped the pan and added Bars RMS.

At home (120 mi later), pan is slightly oiled, so added Blue Devil RMS planning to drive 150 miles then change the oil to spec (I'd read that the Blue Devil is more effective).

Within 10 miles got the first CEL and the P0021 code along with intermittent hesitation over 40mph. Started reading here and everywhere about this code. Also drove it another 100 miles and the leak almost stopped, just a little wet but zero drips. The RMS sealant seems to be effective.

Before changing oil to 5w30, I did try adding heavy Risolene to increase oil pressure, figure it was worth a try as the Blue Devil reduces viscosity and that is exactly when the code started, but the code continued.

Changed oil to fresh 5w30 "high mileage" Mobil 1 regular oil. Drove ~50 more miles, but code continued. I read how sensitive this engine is to additives*, so I changed the oil again to regular 5w30. Still getting the P0021 code, but not as quickly.

I pulled both the solenoids (very easy), checked operation, cleaned with carb cleaner, reinstalled. I'd thought the RMS sealant may have affected rubber parts, but there are none, just small screens, but they were already clean. Still getting the P0021.

Question - does anyone think changing the oil to 10w40 will increase the oil pressure enough and eliminate the P0021? I'd read on a Q35 forum that a blown internal gasket can reduce oil pressure to the cam shaft. Very expensive, hope that's not it.

* on the additives, hard to believe from my post, but I'm not into adding anything to my oil. I'd never had an RMS leak before, but I'd read how effective the RMS sealer can be, especially the Blue Devil, and it might save or postpone a $600 fix.

Thanks in advance for any help.

Follow up -

Got back to working on this. I found that running it with the bank 2 cam position sensor removed would stop the P0021, but instead with a code P0345 plus CEL for the CPS not working (of course). The reason for running like this is that it doesn't go into "limp mode" on this code so my son was able to drive it locally til I got time to figure it out. It was just harder to start and the CEL light on.

I bought a cheap VVT solenoid knock-off on ebay for only $33, not to use it, but to install it in place of the existing OEM solenoids to test operation since you can't pull these to test while running. They operated just fine. I did another oil flush and put the CPS back, but still got the P0021 codes.

Reading more about how the solenoids are powered by oil, it is stated the P0021 means the ECU detects the cam as "over-advanced" so I started thinking about oil pressure and tested it. A little hard to get to the sensor, but I was able to get a gauge on to read 30 psi at idle and 60 psi at 2000 rpm. The solenoids don't operate until 2000 rpm and full open past 3000 rpm, so I was thinking the pressure might be too high.

I was about to take it to a local indy mechanic when I thought I'd try putting on a new oil filter. It immediately ran with NO MORE CODES! So, even though the oil/filter was just changed before purchase and then I did the sealant additive + flushes, I didn't bother to change the filter thinking it was ok. I'm guessing the filter was clogged from the sealant and flushes and the oil routed around it with a pressure the solenoids didn't like. So far we've got over 100 miles now with no codes.

A little frustrating, and maybe $100 worth of oil, parts, etc, but now it is running great! The good news is the Blue Devil RMS sealant worked great (so far) and that's a big savings. At purchase oil was dripping but it hasn't leaked for two weeks since.

Hope this helps somebody.

PathyPop wrote:
I pulled both the solenoids (very easy), checked operation, cleaned with carb cleaner, reinstalled. I'd thought the RMS sealant may have affected rubber parts, but there are none, just small screens, but they were already clean.

Hi Pop,

When you pull the solenoid from the unit (i.e. by removing the one screw), what seals the part which you pull out? Can you clean the screens by just removing the one screw and pulling on the solenoid? I can't quite picture it.

Thanks,
Gary

PathyPop wrote:Follow up -

Got back to working on this. I found that running it with the bank 2 cam position sensor removed would stop the P0021, but instead with a code P0345 plus CEL for the CPS not working (of course). The reason for running like this is that it doesn't go into "limp mode" on this code so my son was able to drive it locally til I got time to figure it out. It was just harder to start and the CEL light on.

I bought a cheap VVT solenoid knock-off on ebay for only $33, not to use it, but to install it in place of the existing OEM solenoids to test operation since you can't pull these to test while running. They operated just fine. I did another oil flush and put the CPS back, but still got the P0021 codes.

Reading more about how the solenoids are powered by oil, it is stated the P0021 means the ECU detects the cam as "over-advanced" so I started thinking about oil pressure and tested it. A little hard to get to the sensor, but I was able to get a gauge on to read 30 psi at idle and 60 psi at 2000 rpm. The solenoids don't operate until 2000 rpm and full open past 3000 rpm, so I was thinking the pressure might be too high.

I was about to take it to a local indy mechanic when I thought I'd try putting on a new oil filter. It immediately ran with NO MORE CODES! So, even though the oil/filter was just changed before purchase and then I did the sealant additive + flushes, I didn't bother to change the filter thinking it was ok. I'm guessing the filter was clogged from the sealant and flushes and the oil routed around it with a pressure the solenoids didn't like. So far we've got over 100 miles now with no codes.

A little frustrating, and maybe $100 worth of oil, parts, etc, but now it is running great! The good news is the Blue Devil RMS sealant worked great (so far) and that's a big savings. At purchase oil was dripping but it hasn't leaked for two weeks since.

Hope this helps somebody.

This is great info.. Thank you for your contribution !

attofarad wrote:When you pull the solenoid from the unit (i.e. by removing the one screw), what seals the part which you pull out? Can you clean the screens by just removing the one screw and pulling on the solenoid? I can't quite picture it

There is an "O" ring that seals the core actuator. Yes on the removing the one 10mm bolt and gently pulling/prying the solenoid. Here's someone else's youtube video of the actuator core that slides out:

https://www.youtube.com/watch?v=Lr9RxrHEyrU

There is really little reason to remove the whole body/core because it doesn't wear and you just need test the solenoid with 12v and clean those fine screens as they would plug up first before the oil pathways in the body. Removing the full unit also risks having a leak and buying a new gasket. Either way, removing the unit takes about 15 min but getting just the core out takes 3 min.

Seems these are a real problem on the "HR" versions of the VQ35, in the "high revving" Z's, G's, Maxima's, etc. Not quite as much with our truck versions.

Thanks for the reply, and the video link. From a quick glance, it seems that there is a coolant pipe in the way of pulling just the solenoid on the passenger side, so I might need to remove the 3 bolts (then the 1), instead of just the 1 bolt. I'll take a better look over the weekend.
Thanks again,
Gary

attofarad wrote:seems that there is a coolant pipe in the way of pulling just the solenoid on the passenger side

Ahh, I just checked (my son's), you're right. Our problem code was the P0021, driver's side. Either way, all or just the core, it's easy. Good luck.

PathyPop wrote: ↑

Thu Apr 06, 2017 11:56 am

attofarad wrote:When you pull the solenoid from the unit (i.e. by removing the one screw), what seals the part which you pull out? Can you clean the screens by just removing the one screw and pulling on the solenoid? I can't quite picture it

There is an "O" ring that seals the core actuator. Yes on the removing the one 10mm bolt and gently pulling/prying the solenoid. Here's someone else's youtube video of the actuator core that slides out:

https://www.youtube.com/watch?v=Lr9RxrHEyrU

There is really little reason to remove the whole body/core because it doesn't wear and you just need test the solenoid with 12v and clean those fine screens as they would plug up first before the oil pathways in the body. Removing the full unit also risks having a leak and buying a new gasket. Either way, removing the unit takes about 15 min but getting just the core out takes 3 min.

Seems these are a real problem on the "HR" versions of the VQ35, in the "high revving" Z's, G's, Maxima's, etc. Not quite as much with our truck versions.

Bringing up old thread...
Is there a pic showing WHERE these solenoids are? Needless to say, all the videos I've come across don't work, LOL.

Back of the timing cover, one on each side: