Diagnostic Trouble Code P0012

P0012 “Camshaft Position A – Timing Over-Retarded or System Performance (Bank 1)”


What is code P0012?

Code P0012 stands for “Camshaft Position A – Timing Over-Retarded or System Performance (Bank 1)”. This diagnostic trouble code can happen for a number of reasons related to the camshaft(s) inside your engine. Therefore, it is important to have a qualified technician diagnose the specific problem that caused the code to be stored in your vehicle’s computer.

Get this checked out soon by a CarAdvise shop, where the work will be guaranteed, and one of our expert techs will review any repair orders.

What does code P0012 mean?

When a diagnostic scan of your vehicle reveals a code P012, a technician will identify that there is something going on with your camshaft timing. The camshaft is responsible for making sure that air and fuel enter the combustion chambers and exhaust gases exit at just the right time for your engine to run properly.

Driven by a timing belt or chain, the camshaft opens and closes each of the intake and exhaust valves in your engine – up to thirty two of them. In order for your engine to run efficiently, or at all for that matter, the camshaft(s) must rotate at the correct speed and at the proper time in relation to other events, including the rotation of the crankshaft.

On single overhead cam (SOHC) engines, a camshaft actuates both the intake and exhaust valves. But in a dual overhead cam (DOHC) engine, there is a separate camshaft for the intake and exhaust functions. Code P0012 relates to the intake camshaft.

Because the timing of the camshaft is so critical, auto manufacturers have placed sensors inside the engine to monitor the camshaft(s) and their exact position and speed at all times. The data from the sensors is transmitted to the vehicle’s ECM (engine control module). If the ECM detects abnormal timing or speed of the camshaft, and that it is operating “too late” in relation to the engine crankshaft, it may store code P0012 and turn on the check engine light.


What causes code P0012?

A number of causes can trigger a code P0012. That is why an accurate diagnosis is essential. Causes of this code include:

Most likely

Other possibilities

  • Engine oil weight not within manufacturer’s specifications
  • Faulty wiring to the camshaft position sensor or camshaft VVT actuator
  • Worn timing chain or belt tensioner
  • Loose or worn timing chain or belt
  • Low oil pressure or level
  • Oil sludge buildup inside engine


What symptoms are associated with this code?

Common signs associated with a code P0012 include the following:


How does a technician diagnose code P0012?

If a diagnostic scan of your vehicle indicates a code P0012, a technician will perform tests to pinpoint the problem. These tests include checking for any related trouble codes. The technician will also use the scan tool to read the live data of the camshaft position sensors during a variety of operating conditions and ensure the data makes sense and is consistent. If available on that vehicle, a camshaft VVT actuator test may be run on the diagnostic tool. The technician may also insert a tiny camera into the engine without disassembling it, in order to inspect the timing chain and tensioner for severe wear.


How serious is this code?

In some cases, you might not notice any significant changes to your vehicle when a code P0012 is indicated. But ignoring the check engine light can lead to significant problems – and even catastrophic engine failure. This code in particular can signal something as small as a poor connection in a wire, or as bad as a timing chain component that is failing. Without knowing exactly what is causing the code, the vehicle should not be driven or even started up more than absolutely necessary.

Get this checked out soon by a CarAdvise shop, where the work will be guaranteed, and one of our expert techs will review any repair orders.


Related Diagnostic Trouble Codes

P0011Camshaft Position A – Timing Over-Advanced or System Performance (Bank 1)”

P0014Camshaft Position B – Timing Over-Advanced or System Performance (Bank 1)”

P0015Camshaft Position B – Timing Over-Retarded or System Performance (Bank 1)”

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