Mazda3 Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
297 Posts
Discussion Starter #1
I'm trying to repair a P0012 code on a 2010 Speed 3 for a fellow church members grandson.

History: The kid came home with the car about two months ago after buying it from a buy here pay here lot. The car had a check engine light on. The boys parents were not thrilled as the car is a modified ricer/tuner. It has had some modifications done and some that have been undone as evidenced by the hole in the right fender, front mount intercooler and piping in the back hatch area as well as 2 non stock Mazda air intakes, wiring harness re-routing under the hood etc...

The kid took it to a repair shop that had it for two weeks and then informed the kid that there was nothing they could do about it because of the "modifications". That's when the grandfather asked me if I could look at it.

So.... the kid drops the car of at my house while I'm at work. His grandad told me he thought it was a Mazda 6 so up to this point I wasn't sure what kind of Mazda it was as the grandad was only guessing. He said he just needed me to fix his check engine light issue to make it through emissions inspection. I pull up to find a lowered, tinted window, cat exhaust only with a 4 inch tailpipe, hole in the fender, tires worn to the steel belts and leaking due to lowered negative camber suspension, fuel gauge/odometer inop., short shifter with torn out boot, wrong air intake with no filter, rode hard piece of junk.

Now for my repair history. Installed new tires as it wasn't safe to drive. Installed a Corksport stage 1 SRI just to have a filter as it was way cheaper than buying the OEM assembly. Pulled 3 rear O2 codes, P0012- VVT cam over retarded, 2 misfire codes.

Found the rear O2 had been replaced with a universal connect to the original harness type. The wiring was corroded green and a couple had broken. Replaced the sensor with Denso unit which fixed the 3 codes and allowed the Cat monitor to finally run and thankfully passes every time.

I first addressed the P0012 code by doing a synthetic oil change as the oil was over a quart low and looked like black water. Didn't fix it.

After driving it with the new SRI, rear O2 and oil change, everything is good except the recurring P0012.

I tried to access the ECU with a Snap On Solus Ultra scan tool but could not communicate. Was trying to get into it to do bi-directional tests on the VVT system.

Went the manual route. Connected a cheap glorified code reader to access the VVT duty cycle and VVT variation from desired position PID's. While revving the engine the ECU called for duty cycle and the variation would go to a negative reading. Connected a VVT solenoid to the connector that I had from a old NA 2.3. It is the same P/N. While revving the engine I verified that the ECU control to the VVT sol. was indeed activating it and moving the plunger from the static retard position to the advanced position. I then connected power and ground to the VVT sol. on the engine with it idling to verify that the sol. and VVT gear were responding. Connected, the VVT would go to full advance and the engine would idle rough indicating that it was working. Did this several times. The scan tool read minus 20ish degrees with VVT energized. As I did it repeatedly it eventually read minus 6ish degrees although it still did the same rough idle.

Decided to check the crank/cam timing. Pulled valve cover and HPFP and installed the crank pin and cam tool. Timing is perfect. Noticed that the crank sensor was a bit retarded on the 20th tooth. Adjusted crank sensor to dead center postion, wiped cam sensor clean of any debris, installed the VVT sol. from my 2.3 NA just to verify that the VVT sol. was ok. Checked VVT filter in cam cap- OK and free of debris and reassembled everything to try it again and see if crank sensor adjustment, different VVT sol. would make a difference. It did not. Set P0012 again.

Verified so far that is good:
VVT solenoid
VVT signal from ECU
Engine timing chain and timing all OK
Oil pressure light goes out and stays out when running
VVT activates when jumped and also by ECU per scan reading

Two things unknown and more if you see something I'm overlooking:
-ECU issue- why does it read minus numbers when it is advanced either by ECU or jumping?
Is this normal and is it possible this ECU has a tune on it which could be causing the issue and not allowing a regular scan tool communication. Only my 2 different code readers work.
-VVT gear issue- could it be bad even though it is moving when jumped or by ECU activation per rough idle or scan reading respectively?

Look forward to everyone's insight. Thanks for reading.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #2
Had some input from the mazdaspeed forum. Kind of told me what I already knew.

Because the code is a two trip failure meaning it doesn't turn on the CEL until the second key cycle/failure, the kid has decided he wants to start and drive it after a CEL clear and cold soak until the monitors pass and then proceed straight to the emission test place so it will technically pass with no CEL on and monitors ready. It should work for him although it is not fixed.

His money I suppose.
 

·
Registered
Joined
·
502 Posts
Had some input from the mazdaspeed forum. Kind of told me what I already knew.

Because the code is a two trip failure meaning it doesn't turn on the CEL until the second key cycle/failure, the kid has decided he wants to start and drive it after a CEL clear and cold soak until the monitors pass and then proceed straight to the emission test place so it will technically pass with no CEL on and monitors ready. It should work for him although it is not fixed.

His money I suppose.
Maybe that works in Tennessee. It wouldn't in Colorado. My daughter's 2007 M3 had a CEL from the IMRC actuator. That one take five engine cycles to register as a CEL, but if you look on a proper scan tool it shows up as a pending code. From what I read on the website for our air quality testing, they check for stuff like that and you won't pass.

But there is a legit work-around. We have drive-by air testers set up in various places in Boulder and Denver. Every time you drive by, it tests and records your emissions (and your license plate) using a variety of techniques. If you register two clean "drive bys" in a year, it send you a note that you don't have to visit the testing station, just send in your $. The testing at these drive-by stations is stricter than the tailpipe test at the test station. But, if your car is in good working condition and you have mods done on it, or have CELs, then just register a few good drive bys and you are good to go.

I seriously was wondering why we've never had to take our Explorer in for a test. And now I know. My wife frequently drives around in Boulder!
 

·
Registered
Joined
·
297 Posts
Discussion Starter #4
Maybe that works in Tennessee. It wouldn't in Colorado. My daughter's 2007 M3 had a CEL from the IMRC actuator. That one take five engine cycles to register as a CEL, but if you look on a proper scan tool it shows up as a pending code. From what I read on the website for our air quality testing, they check for stuff like that and you won't pass.

But there is a legit work-around. We have drive-by air testers set up in various places in Boulder and Denver. Every time you drive by, it tests and records your emissions (and your license plate) using a variety of techniques. If you register two clean "drive bys" in a year, it send you a note that you don't have to visit the testing station, just send in your $. The testing at these drive-by stations is stricter than the tailpipe test at the test station. But, if your car is in good working condition and you have mods done on it, or have CELs, then just register a few good drive bys and you are good to go.

I seriously was wondering why we've never had to take our Explorer in for a test. And now I know. My wife frequently drives around in Boulder!

I don't live in a emission county so I don't know exactly how TN works. In Vermont where I lived for 17 1/2 years it would work. There you had to have a working KOEO CEL, no KOER CEL, and the scanner had to show the CEL was commanded off, and all but 2(or 3 depending on vehicle) monitors had to be ready. So with that scenario you could have a pending code and still be able to check off all the boxes. TN may have a pending code failure also. I'll be interested to see what happens when he goes.
 
1 - 4 of 4 Posts
Top