What is the "cleaning mode of the variable valve timing control function"

[josephf31]

Hi all!

Just got a used 2010 CX7 a few weeks ago, 77K supposedly new timing chain -- trying to eliminate an intermittent P0012 CEL. Just replaced the OCV, no love...the manual says;

Note
* This DTC is detected as an intermittent concern.
* The intermittent concern might be removed using the cleaning mode of the variable valve timing control function

Couple of questions -- 1) 'detected as an intermittent concern' -- in English does that mean it can come and go? 2) what *exactly* is the "cleaning mode of the VVT control function" and how is it done?

Hopefully some of you can help me out with this, it's the only issue I have and I love the vehicle...thanks!!

Joe

[josephf31]

HELLO? ANYONE?

[Tomas]

Do you have a 2.5L engine?
If you do, you have VVT on the exhaust cam. The cleaning mode is something the PCM engages in when certain conditions are met like deceleration and consequent fuel cut. No idea how you can engage that manually.

This forum focuses on the 2.3L DISI engine. Someone may be able to help but its unlikely.
I would suggest looking at the VVT unit and chain itself if you already changed the OCV out.

[josephf31]

Thanks for the response, I do *not* have a 2.5 motor I have the 2.3 turbo. I replaced the OCV myself, the code did not go away, since then it's been to the Mazda dealer and he has replaced the timing chaing, VVT actuator and oil cooler and after 2 (pending 3) visits the code will NOT go away. I have reset the ECU still nothing. I am getting very frustrated after having paid the dealer almost $2000 and nothing has changed.

My thoughts are that it is a PCM issue...since just about all of the mechanical parts are new.

Ideas? Thank you.

[josephf31]

hello

[JSmith]

If you have the same motor as most of us here...have you tried searching the forums for the CEL?

LMGTFY

Try this one.
P0012 code...

[5doorsoffury]

Did you try to clean or replace the cam sensor on the VC?

Now you said it was timed by mazda so i will guess the timing is good along with the vvt.

The cam sensor reads the reluctor wheel on the intake camshaft. If it is off compared to what the computer reads fron the crank sensor vs vvt commanded it figured out that the cam position is no bueno. Since we assume that mazda did a good job with the vvt then it is a sensor misreading. The sensor is misreading because it is bad or crap on the sensor skewing the reading or the reluctor wheel on the cam is off.

Try cleaning the sensor. Then try replaceing the sensor. Then try comparing your cams reluctor wheel with pictures of some mazdaspeeds online by lineing up the lobes.

Also check for damaged wires. Gl

[josephf31]

this is driving me nuts...it's hard to believe that changing oil will fix the problem; and nobody ever answered the question of whether or not a PCM reflash/replacement would fix the issue.

Also a bad CPS would throw a code P0340 I have not had that one, so is it worth replacing the cam position sensor? thx

[JSmith]

No one named @josephf31; read the thread I pointed them to. If they had read to at least post #15 instead of asking for the spoon AGAIN, they would have seen something about a PCM reflash.

[josephf31]

I read EVERY single post, took me a while, lots of people ASKED if a PCM reflash/replace would fix the issue, but nobody ANSWERED...

Post #15

"I am also in the same boat. The car is a 2007 CX-7. I recently rebuilt the engine with new pistons (20 over), all new bearings, rebuilt head, new timing chain and tensioner, new OCV and actuator, both new camshaft, good oil pressure. After 2 on/off cycles and driving the car I get DTC P0012.

What do you guys think about this? Specifically the corrosion on the PCM circuit board shown on page 32. I can't read Russian. http://alflash.com.ua/Learn/mazda_cx7.pdf

I also found Mazda TSB 01-042/06 regarding reoccurring P0012. The proposed solution is to reprogram the PCM. Has anyone researched this?"

Post #16

"Being in the same boat as you with all of the related sensors and actuators replaced the next step is a PCM reprogram/replacement. I am going to take my car in to Mazda at some point and let them take a crack at it just to see what they're recommendation would be. Last time I took it in they took it on a 17 mile joy ride to tell me it had a cracked spark plug that wasn't even part of my initial concern so needless to say I'm a little hesitant to go back.

I followed the P0012 diagnostic procedure and every single item checks out OK, the last step is possible PCM malfunction but I don't have an MDS at my disposal.

Also the PCM's are very expensive and need programmed, so I have just been dealing with the CEL. I'm hoping someone will report back to this thread with their findings."

STILL no answer...