|Trouble Code||Fault Location||Probable Cause|
|P0012||Camshaft position (CMP), intake/left/front, bank 1 timing over -retarded||Valve timing, engine mechanical fault, CMP actuator|
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What Does Code P0012 Mean?
In most cases if P0012 comes up it is due to lack of oil lubrication. The best way to rectify the situation is to apply an engine cleaning product and do an engine rinse before re-installing a new VCT/VVT solenoid. If that is not done you will have near future failure of the new VCT/VVT solenoid. It is very important to note in the new VCT/VVT engines they are very susceptible to lower cost oils. You need to purchase high end oils in order to have a longer lasting camshaft oil timing system. You definitely get what you pay for in this case.
- Bank 1 or bank A VVT or VCT solenoid failure. Different manufactures use these terms but both systems are the same.
- VVT- Variable Valve Timing
- VCT- Variable Camshaft timing
- You have an intake camshaft solenoid error usually. Not manufacturer specific, is a generic code.
- Bank A or bank 1 if a 4 cylinder engine. Depending on the type of engine if you have two banks then will have a bank 2 error. Then go into a P0022 code situation.
What are the common causes of code P0012 ?
- Why did the solenoid fail? It is usually from an oil maintenance problem
- Poor choice of oil product for this particular engine- causes carbon build up in the VCT engines and will produce small ball like substance (carbon build up). This was not seen before VVT engines were introduced. This is what causes the filter blockage of the solenoid and causes it to fail and potential engine failure.
What are the symptoms of code P0012 ?
- Loss of gas mileage
- Engine stalling
- Possibly engine failure
- Engine contamination
- If the actual solenoid does fail this will cause a retardation of the intake valve operation
- Check engine light will appear
- Possibly camshaft failure due to lack of lubrication
How do you troubleshoot code P0012 ?
- Use a multi meter and take resistance
- As a general rule- every terminal needs to be checked for a solenoid failure. If it does not have a 7-12 ohm on the multi meter, it is most likely failed. Always pin test from the valve solenoid to PCM or ECM.
- Pin test means you must check continuity in the wiring harness between the actual valve solenoid and the brain (computer pcm/ecm)
- While pin testing in back probe, wiggle test all related harnesses and observe readings on vault meter/multi meter
- Check all engine grounds
- Also, clean and tighten every harness terminals from the valve solenoid to the pcm. The integrity of those contacts must be tightly mated and lubricated with grease to make sure full electric contact is present. The misdiagnosed problem is engine vibration which will loosen the harness connecters because most variable cam shaft timing systems rely on high revolution engines. So, any loose wiring or connections may cause this code. It does not mean the actual valve is a problem.
- First check the resistance of the actual valve. Most only have two terminals, will likely present 7-12 oms.
- Often the exhaust camshaft valve solenoid will be the issue, so interchange the two valves one for another and clearing codes.
- If the code changes to the exhaust then it is P0015
- The intake and the exhaust solenoid will have the same type of connection and are interchangeable. Try interchanging one solenoid for the other. If after erasing all present codes, a different code comes back, then you have essentially eliminated the actual valve solenoid and have saved hours of diagnostic work. By interchanging most times if one code changes to the other, you can got your parts guy and ask for the valve solenoid.
- The failure of the solenoid VVC or VCT is usually due to oil blockage from the screen/filter.
Codes Related to P0012
Type B codes- will erase itself without a scanner.
Type A code there is something else.
If these codes show it is unlikely to be the valve
If the initial P012 sets and other codes are present then erase all codes and do five camshaft drive cycles and then re-investigate which codes come back. If any of these codes are present disregard and erase. If they come back it is electrical wiring or connection failure.
PCM/ECM has a particular algorithm to follow. If the valve does not respond to the criteria of the computer, it will recognize the algorithm. So, usually when the P0012 code shows it is failure due to lack of maintenance.
Most P0012 codes are almost always a result of bad oil changes and lack of car maintenance in regards to engine lubrication.
BAT Team Discussions for P0012
- Mazda 6 3.0 liter Bog and not wanting to go
I pulled the codes and found a P0011 and a P0012 Bank 1 cam over advance and over retarded. When you start it up it runs ok. But after it runs for about five minutes, it will idle ok but if you give it any pedal it spits and sputters. if you attempt to test drive it, you will get about a half mile d...