The Nissan Path

2006 vq40de pathfinder.
A few years ago it popped either p0011, p0021 or both. The timing chains were changed ( also had noisy guides) and it still popped both codes. It was parked for a while, and i finally tried diagnosing this. I changed oil weights 10w40, pulled both solenoids and cleaned them, but both codes came back. Today i just repaced both solenoids, and after about 4 starts with no pending codes, i took it for an extended drive and both p0011 and p0021 both came up at the same time.

what would cause both to come up at the same time? Timing chain/tensioner being off/loose? 2 bad cam sensors( with no p0345)?

Probably unrelated, but the truck killed 2 batteries in a row ( but now is fine) and has a tire pressure light that is stuck on with all tire pressures at 35( i assume a bad sensor).

Thanks in advance for any ideas.

For those codes service manual lists the following possible reasons:
● Crankshaft position sensor (POS)
● Camshaft position sensor (PHASE)
● Intake valve timing control solenoid valve
● Accumulation of debris to the signal pick-up portion of the camshaft; this is intake camshaft, which rotor is chipped at the end (has teeth for sensor to pickup signals). I don't know, but maybe it can be seen through sensor insertion hole and and cleaned, if teeth picked up something...or better disassembled and cleaned)
● Timing chain installation
● Foreign matter caught in the oil groove for intake valve timing control

...and later for PHASE camshaft sensor, which may be underlying cause:
● Harness or connectors (The sensor circuit is open or shorted)
● Camshaft position sensor (PHASE)
● Camshaft (Intake)
● Starter motor
● Starting system circuit
● Dead (Weak) battery

Thanks! Those were the culprits i was trying to narrow it down between.
Since they both pop up at the same time i can likely exclude either cam sensor, or debris (unless there is a shared oil feed, or a shared ground or power wire).
So 3 things related to that list that make sense to me:
1. Low voltage (looks fine on the gauge)
2. Poor grounding ( if shared between both cps or solenoids)
3. Low oil pressure (looks fine on the gauge)
4. Timing chain stretched/loose

Today i ran for probably around 20 minutes with no codes (none pending) after swapping in new solenoids, and they only came up after i cycled the ignition 6 times without starting.
Since they came up with the engine not running i am starting to suspect its voltage related. Also the timing chain and tensioner are relatively new, although maybe the install fixed one problem (loose chain because of worn guides)and replaced it with another( loose chain because of....).

I guess in order of cost ill start with
1. Swap batteries with one of my other cars and see if it keeps away codes for a few days.
2. Remove clean, reinstall both cam sensors.
3. Replace cam sensors.
4. Timing chains ( at least i have the tools and practice to do this again haha)
5. Ls swap it

The only time I've seen those codes on a VQ40DE is when the primary timing chain was installed a tooth off. They used to occur more frequently on the VQ35DE engine and they were most often caused by bad intake valve timing actuators and/or low or sludged oil.

smj999smj wrote:The only time I've seen those codes on a VQ40DE is when the primary timing chain was installed a tooth off. They used to occur more frequently on the VQ35DE engine and they were most often caused by bad intake valve timing actuators and/or low or sludged oil.

I strongly agree, very common on the VQ35DE, not so much on the VQ40.

I appreciate the help from both of you.
I'm thinking Voltage or timing chain (tooth off) seem to be 50/50 odds.

A few more questions.
1. Are the two codes (p0011 and p0021) specific for cam-timing "too advanced" errors...or do they come up for "too retarded" as well?

Related If a chan slipped one tooth, it would likely have to be the crank, and not both cams. This would cause cam-retard and not advance. Correct?

Aside from a tooth off (advanced) on install, would a collapsed tensioner, chain slip, or stretched chain cause a cam advance, or cam retard?

Thanks again.

Codes will set for out of time, retarded or advanced. With both banks triggering codes, I would suspect that it would be off at the crank. It really doesn't matter because if the chain is off, you still have to pull the front cover off, regardless. If this is the case, I would recommend a new, primary chain because it's hard to see the off-colored links on the primary chain once it has been removed and been in service for many miles. Timing chain stretch is practically unheard of on VQ-engines. If a tensioner has collapsed, you would likely hear timing chain slap or rattle. I had a bolt break on my primary tensioner which caused the tensioner to drop back against the inside of the cover and the chain to slack; it made a hell of a racket as the timing chain smacked against the upper chain guide!

smj999smj wrote:Codes will set for out of time, retarded or advanced. With both banks triggering codes, I would suspect that it would be off at the crank. ............ I had a bolt break on my primary tensioner which caused the tensioner to drop back against the inside of the cover and the chain to slack; it made a hell of a racket as the timing chain smacked against the upper chain guide!

thanks for the clarification on both advance and retard of cams causing 21 and 11 codes to pop. When your tenshioner collapsed did both p0011 and p0021 codes pop? What orher codes came up?

My tensioner didn't really collapse. The updated chains had been installed by the dealer previous to me purchasing the vehicle and I think the mechanic over-tightened the tensioner bolts, causing one to break. I really wasn't concerned about the codes at the time because I knew there was a mechanical failure and was more worried about my engine grenading! After I replaced the chains, guides, etc., I just erased the codes. I don't remember if I ever checked for what they were.
I did replace upper chains and tensioner "feet" on a Frontier VQ40DE and reused the primary chain and got one of the cams off-time, which set off the P0021 code. I ended up have to re-pull the front cover and used a new, primary chain to make sure I had the marks right. Lesson learned!