If you notice a P0012 OBDII error code, it’s generally indicative that there are problems with your camshaft’s VVT (variable valve timing) solenoid. Just like every other diagnostics trouble code, P0012 has its own definition, which in this case, is defined as “Camshaft Position A – Timing Over-Retarded (Bank 1)“. So, what does this mean?
Well, the short of it is that your car’s ECU has noted that there’s a slight difference in the recommended intake camshaft position angle, in relation to the the actual angle that your camshaft has. You’ll usually see this code when the camshaft has remained in a retarded position. Or, the camshaft position is above the maximum recommended value.
In simple terms, this means that the timing of your engine is off, or the timing is not measured correctly. In most cases, the latter is the problem. And in particular, the problem is specific to Bank 1 of your engine, which is where cylinder 1 is located. To get a better understanding of how to fix the P0012 error code, we need to understand what’s causing it in the first place.
What Causes A P0012 Error Code?
As I noted earlier, when you see a P0012 error code, it’s mostly connected to the variable valve timing mechanism of the engine. This is a specific mechanism that alters the timing of the valve lift event. It’s been used since the 90s and now it is a standard on all cars, by improving performance, emissions, and fuel efficiency of the vehicle.
But sometimes, the variable valve timing (VVT) system can cause problems, such as the P0012 error code. Here are just some of the reasons why you’re seeing this code appear:
1) Bad Or Contaminated Solenoid Screen
Your car’s VVT solenoid screens resemble small filters. When they get clogged up, they will cause problems such as the P0012 error code. At worst, all you need to do is remove the solenoid screen and get it cleaned. Sometimes, this is enough to restore the proper function of the VVT system. The whole VVT has to be disassembled and refurbished to fix the issue.
2) Bad Camshaft Variable Valve Timing Solenoid
The second most probable cause for the P0012 code is a bad camshaft VVT solenoid. This solenoid is the component that activates the actuator and tells the oil control valve to send oil into the actuator. These solenoids are electrical components and their circuit can short out or they could completely fail. The only way around will be to replace the solenoid with a new one and call it a day.
3) Bad Variable Valve Timing Actuator
Another probable cause for the P0012 code is a bad VVT actuator. This is a device that works with the oil pressure that is sent from the oil control valve by the instructions of the VVT solenoid. The actuator is a mechanical device, which can fail. Given systems like these where the tolerances are almost non-existent, it can cause a lot of issues.
4) Running The Engine On Low Or Incompatible Oil
The next factor that could cause the P0012 code is when you run the engine on low motor oil or use incompatible motor oil. These VVT systems need oil to work, so if there is not enough oil in the system, or if you run any type of oil that was not specified by the carmaker, it can cause issues. So, make sure that you stick to the right viscosity of oil… Not thinner or thicker than the one recommended.
5) Worn Out Timing Chain
Another probable cause for the P0012 code is a worn-out timing chain. Modern cars require the replacement of timing chains at the right interval. If you delay this process, there will be some slack in the chain, and this will cause the camshaft to lose timing. So, it could throw a code like in this case. This is why you need to replace this timing chain on time.
6) Broken Timing Chain Tensioner
On a similar note, there’s also a broken timing chain tensioner or guide. These components keep the right tension on the timing chain itself. So, whenever some of these components fail, it’ll develop play, and you will start to notice symptoms like the P0012 code, among others. So, make sure you check that timing chain tensioner.
Symptoms Of A P0012 Error Code
Aside from noticing a P0012 error code, there are other symptoms that accompany faults with your car’s VVT solenoid. These include (but aren’t limited to):
- Check Engine Light – The CEL (check engine light) is your car’s way of telling you that there’s an error code logged. If you have an OBDII code scanned, then the CEL will light up alongside it.
- Decreased Fuel Efficiency – If the VVT system malfunctions, your car’s engine won’t have the same level of performance or fuel economy as it used to have.
- Engine Works Strangely – On that note, with a faulty VVT system, your engine might struggle to start properly. Or, it suffers from a poor idle. Alternatively, it might even stall, before then having trouble starting.
- Rattling Noises – Since the VVT ties in closely with the timing chain, a loose timing chain will emit rattling noises. It’s either worn out, or the tensioner is broken and the chain has a lot of slack in it.
How To Diagnose A P0012 Error Code?
If you want to troubleshoot and fix a P0012 error code, there are a few things you can do:
- The first thing that you want to do is check your VVT solenoid and the solenoid screens.
- That screen is the wire mesh that cleans out motor oil and makes sure that nothing bad enters the actuator. If the screen is dirty, make sure that you clean them out.
- The next thing you should diagnose is the VVT solenoid itself. For this, you will need a multimeter tool to check if it’s working or not.
- Your VVT solenoid is often located on top of the valve cover or close to the valve cover. For the right placement, you can refer to a repair manual.
- If the solenoid is good, then you can look for your problem elsewhere. This could be the actuator itself, or the valve body where the solenoid goes. The timing chain and the tensioner are other possibilities.
Granted, if the VVT solenoid itself is the issue, then replacing it isn’t terribly expensive. You’ll have to pay somewhere in the range of $80 to $250 for the parts alone. Meanwhile, the labor is also going to cost you between $100 to $150.
However, if the VVT actuator is the problem, it’ll be rather expensive to replace this one. It’ll cost you somewhere in the range of $850 or thereabouts. So, that’s $300 for the part and $550 for the labor involved.
A timing chain replacement is also quite expensive, averaging between $1,000 to $1,500 to replace the timing chain/belt and the tensioner. So, it’s worth replacing the VVT solenoid before it causes other side effects down the line.
