P0012: Intake “A” Camshaft Position Timing - Over-Retarded (Bank 1)

Is your check engine light on and is the scanner logging a P0012 code? Then your vehicle might have issues with the engine’s camshaft position and timing.

This guide explains what code P0012 means, what causes it, and what you can do to fix it.

What Does Code P0012 Mean?

Code P0012 is a diagnostic trouble code that stands for “Intake (A) Camshaft Position Timing – Over-Retarded (Bank 1)”. It means that your vehicle’s powertrain control module (PCM) has detected that the timing of the intake camshaft on Bank 1 is retarded or delayed compared to the position of the crankshaft. This causes the rotation of the camshaft to lose its optimal timing, resulting in poor engine performance and loss of power.

The “A” in the code refers to the intake camshaft for inline or straight overhead camshaft engines. For V or boxer engines, it refers specifically to the intake camshaft on Bank 1, which is the side of the engine where cylinder #1 is located.

To help explain this a bit more, let’s discuss the relationship between the camshaft and crankshaft. On engines without Variable Valve Timing (VVT), the crankshaft and camshaft are constantly timed the same. On the other hand, on engines with VVT, the camshaft can be indexed to operate the intake valves sooner than the crankshaft.

VVT helps achieve the optimal intake valve opening position, which helps provide low-end torque and better idle quality and emissions.

The vehicle’s PCM/engine control module (ECM) uses camshaft/crankshaft sensors to keep track of the camshaft’s position versus that of the crankshaft. The PCM/ECM uses feedback from the sensor to determine the camshaft’s position and rotation so it can synchronize fuel injection and coil firing.

What Causes Code P0012?

The PCM can log code P0012 for several reasons. In most cases, it is due to a worn or damaged camshaft VVT solenoid and actuator or a worn timing chain. Insufficient or contaminated engine oil has also been known to trigger this code.

Poor maintenance or frequent short trips can also cause engine sludge buildup that affects the VVT solenoid’s ability to do its work as designed.

If the PCM commands more of a camshaft angle change than it receives, this code will be set. The algorithms always have a desired target on various parts of the engine control system and if they can’t reach their desired target even with the actuator maxed out, a code will be set.

Other known causes of code P0012 include a faulty camshaft position sensor or oil control valve. A malfunctioning PCM might also log a false reading, although this is a rare occurrence.

• Damaged variable timing solenoid or actuator
• Faulty camshaft position sensor
• Worn or damaged timing chain
• Bad or contaminated engine oil

Damaged Variable Timing Solenoid or Actuator

A worn or damaged solenoid prevents the camshaft from adjusting itself to the proper timing. It is the most common cause of code P0012, especially if no other codes are recorded.

Faulty Camshaft Position Sensor

A faulty camshaft position sensor can send incorrect data to the PCM, which interprets it as an error in the camshaft’s position and logs the P0012 code.

Worn or Damaged Timing Chain

Over time, the timing chain can stretch out and cause the camshaft to lose its timing. A broken or defective timing chain tensioner has also been known to cause misalignment.

Bad or Contaminated Engine Oil

Low engine oil levels can hinder the VVT system's proper functions, while dirty or contaminated oil can clog the timing valves and cause them to stick.

What Are the Symptoms of Code P0012?

The first sign of code P0012 is often the check engine light, but it may be accompanied by other symptoms. Vehicle owners may have trouble starting the engine or experience rough idling, for instance, while imbalanced camshaft timing can significantly reduce engine performance and fuel economy. Here are the symptoms to watch out for:

• Ignition issues
• Poor idle quality
• Reduced engine power
• Decreased fuel economy

Ignition Issues

The engine may have difficulty starting up or even refuse to start at all, especially in cold weather.

Poor Idle Quality

If the timing of the camshaft position has significantly deteriorated, the engine may idle roughly or stall frequently, especially at low RPMs.

Reduced Engine Power

Failing VVT and camshaft components may lead to the engine struggling to accelerate and gain speed.

Decreased Fuel Economy

Misalignment of the timing of the camshaft’s various components can also cause the engine to consume more fuel than usual, resulting in a noticeably reduced fuel economy.

How to Diagnose Code P0012

Follow these steps below to properly diagnose the error code P0012 and its accompanying symptoms:

Conduct an OBD Scan

Connect an OBD-II scanner to your vehicle’s onboard computer and initiate the scan. Verify if the scanner’s display shows the P0012 code and take note of other codes that appear.

Check the Engine Oil

Make sure the oil is at a sufficient level and is the proper rating for your vehicle. If it is visibly dirty or contaminated, you have to replace both the oil and the oil filter.

Inspect the VVT Solenoid

Look for any signs of damage, such as cracks or leaks. Use a multimeter to check for proper voltage and resistance.

Examine the Camshaft Position Sensor

Check for damage to the sensor or its wires and connectors. You can also use a scan tool to determine if the sensor is transmitting signals correctly.

Check the Timing Chain

Look for stretching, wear, or damage on any of the links. Take note of whether the chain is aligned correctly with the gear teeth.

You should also check for technical services bulletins (TSBs) from your vehicle’s manufacturer if they have specific notes for the P0012 code. TSBs provide helpful information on resolving technical problems for specific makes and models.

How to Fix Code P0012

Here are general steps on how to fix P0012 code issues. The procedure may vary slightly depending on your vehicle’s make and model.

Replace the VVT Solenoid

Carefully remove the solenoid, its electronic connectors, and mounting bolts. Lubricate the new solenoid and seals and secure them in place.

Replace the Camshaft Position Sensor

Disconnect the battery and carefully remove the sensor and its connectors. Replace the O-ring seal and install the new sensor.

Replace the Timing Chain

Remove the old timing chain, clean and lubricate the gears with gear oil, and install a new chain. Ensure proper alignment of the links with its gears and tighten according to manufacturer specifications.

Replace the Engine Oil

Drain the old oil from the engine and refill it with the right type and quantity of oil. You must also replace the oil filter to prevent contaminating the new oil.

Clear Existing Codes

Use the code scanner to clear the codes and test drive your vehicle. If the codes or symptoms return, we recommend having a mechanic check your vehicle.

Other Codes Related to P0012

One or more engine trouble codes may also appear alongside a P0012 code. These codes are typically associated with issues with the camshaft position or the VVT system.

P0010

The PCM has detected an issue with the camshaft or camshaft position actuator.

P0011

Bank 1 of the intake camshaft is ahead of its intended timing and out of alignment.

P0013

The Bank 1 exhaust camshaft control valve has short-circuited or is stuck in an open circuit.

P0016

The data from the camshaft position sensor for the Bank 1 intake camshaft isn’t aligned with that of the crankshaft position sensor.