Variable valve timing (VVT) Generic OBD II Fault Codes:

Variable valve timing (VVT) systems aren’t only used to increase performance. (VVT’s) benefit to fuel consumption and emission are slowly leaving the (EGR) valve in the past.

In theory, maximum overlap is needed between intake valves and exhaust valves’ opening whenever the engine is running at high speed. However, when the car is running at medium speed in highway, in other words, the engine is running at light load, maximum overlapping may be useful as a mean to reduce fuel consumption and emission.

Variable Valve (VVT)
Variable Valve (VVT)

Since the exhaust valves do not close until the intake valves have been open for a while, some of the exhaust gases are recirculated back into the cylinder at the same time as the new fuel / air mix is injected. As part of the fuel / air mix is replaced by exhaust gases, less fuel is needed. Because the exhaust gas comprise of mostly non-combustible gas, such as CO2, the engine runs properly at the leaner fuel / air mixture without failing to combust.

As great as VVT is, it is also vulnerable to some problems. On VVT systems that use oil pressure to actuate the cam phaser, oil quality, viscosity and contamination problems can affect the operation of the phaser. If the phaser does not receive adequate oil pressure, or the oil is the wrong viscosity (too thick or too thin), or the oil is dirty, it may prevent the phaser from working properly. This, in turn, can hurt engine performance, fuel economy and emissions. Such faults will often turn on the Check Engine light and set a VVT-related fault code.

Variable valve timing (VVT) Generic OBD II Fault Codes:

  • P0010….A Camshaft Position Actuator Circuit Bank 1

This code is set when the camshaft is not changing timing because of an electrical fault in the Variable Valve Timing control circuit.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head with number one cylinder (bank 1) on a V6 or V8 engine.

Intake and exhaust camshaft timing is typically retarded at higher RPM to increase power, and advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy. Exhaust cam timing may be retarded when the engine is under load to reduce oxides of nitrogen (Nox) emissions.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position clockwise or counterclockwise to change timing using oil pressure and either a helical gear or lobed or vaned rotor inside the phaser housing.

  • P0011….A Camshaft Position Timing Over-advanced or System Fault Bank 1

This code is set when the camshaft is out of its commanded position and is advanced compared to where it should be.

Intake and exhaust camshaft timing is typically advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head with number one cylinder (bank 1) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0012….A Camshaft Position Timing Over-retarded Bank 1

This code is set when the camshaft is out of its commanded position and is retarded (delayed) compared to where it should be.

Intake and exhaust camshaft timing is typically retarded at higher engine RPMs to improve power.

In applications where VVT is only used on the exhaust cam in an overhead cam (OHC) or dual overhead cam (DOHC) engine, retard is used primarily to reduce oxides of nitrogen (NOx) emissions when the engine is under load.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head with number one cylinder (bank 1) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0013….B Camshaft Position Actuator Circuit Bank 1

This code is set when the camshaft is not changing timing because of an electrical fault in the Variable Valve Timing control circuit.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head on the number one cylinder (bank 1) on a V6 or V8 engine.

intake/exhaust camshaft if the engine only has one camshaft.

Intake and exhaust camshaft timing is typically retarded at higher RPM to increase power, and advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy. Exhaust cam timing may be retarded when the engine is under load to reduce oxides of nitrogen (Nox) emissions.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position clockwise or counterclockwise to change timing using oil pressure and either a helical gear or lobed or vaned rotor inside the phaser housing.

  • P0014….B Camshaft Position Timing Over-Advanced or System Fault Bank 1

This code is set when the camshaft is out of its commanded position and is advanced compared to where it should be.

Intake and exhaust camshaft timing is typically advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head with number one cylinder (bank 1) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0015….B Camshaft Position Timing Over-Retarded Bank 1

This code is set when the camshaft is out of its commanded position and is retarded (delayed) compared to where it should be.

Intake and exhaust camshaft timing is typically retarded at higher engine RPMs to improve power.

In applications where VVT is only used on the exhaust cam in an overhead cam (OHC) or dual overhead cam (DOHC) engine, retard is used primarily to reduce oxides of nitrogen (NOx) emissions when the engine is under load.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head with number one cylinder (bank 1) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0020….A Camshaft Position Actuator Circuit Bank 2

This code is set when the camshaft is not changing timing because of an electrical fault in the Variable Valve Timing control circuit.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

Intake and exhaust camshaft timing is typically retarded at higher RPM to increase power, and advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy. Exhaust cam timing may be retarded when the engine is under load to reduce oxides of nitrogen (Nox) emissions.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position clockwise or counterclockwise to change timing using oil pressure and either a helical gear or lobed or vaned rotor inside the phaser housing.

  • P0021….A Camshaft Position Timing Over-Advanced or System Fault Bank 2

This code is set when the camshaft is out of its commanded position and is advanced compared to where it should be.

Intake and exhaust camshaft timing is typically advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0022….A Camshaft Position Timing Over-Retarded Bank 2

This code is set when the camshaft is out of its commanded position and is retarded (delayed) compared to where it should be.

Intake and exhaust camshaft timing is typically retarded at higher engine RPMs to improve power.

In applications where VVT is only used on the exhaust cam in an overhead cam (OHC) or dual overhead cam (DOHC) engine, retard is used primarily to reduce oxides of nitrogen (NOx) emissions when the engine is under load.

The “A” cam usually refers to the intake camshaft on Dual Overhead Cam (DOHC) engines, or the intake camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0023….B Camshaft Position Actuator Circuit Bank 2

This code is set when the camshaft is not changing timing because of an electrical fault in the Variable Valve Timing control circuit.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

Intake and exhaust camshaft timing is typically retarded at higher RPM to increase power, and advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy. Exhaust cam timing may be retarded when the engine is under load to reduce oxides of nitrogen (Nox) emissions.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position clockwise or counterclockwise to change timing using oil pressure and either a helical gear or lobed or vaned rotor inside the phaser housing.

  • P0024….B Camshaft Position Timing Over-Advanced or System Fault Bank 2

This code is set when the camshaft is out of its commanded position and is advanced compared to where it should be.

Intake and exhaust camshaft timing is typically advanced at mid-range RPM under light load to reduce pumping losses and improve fuel economy.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

  • P0025….B Camshaft Position Timing Over-Retarded Bank 2

This code is set when the camshaft is out of its commanded position and is retarded (delayed) compared to where it should be.

Intake and exhaust camshaft timing is typically retarded at higher engine RPMs to improve power.

In applications where VVT is only used on the exhaust cam in an overhead cam (OHC) or dual overhead cam (DOHC) engine, retard is used primarily to reduce oxides of nitrogen (NOx) emissions when the engine is under load.

The “B” cam usually refers to the exhaust camshaft on Dual Overhead Cam (DOHC) engines, or the exhaust camshaft for the cylinder head opposite the number one cylinder (bank 2) on a V6 or V8 engine.

The timing position of the camshaft is controlled by a cam phaser that is part of the camshaft drive gear or sprocket. The phaser rotates the cam’s relative position using either a helical gear and hydraulic piston, or a lobed rotor or vaned rotor. The phaser uses oil pressure to change cam timing.

check engine light
check engine light
service engine soon
service engine soon
check engine
check engine

How do I reset the “Check Engine or Service Engine Soon” Light?

After you’ve properly diagnosed and fixed the problem that triggered the OBD trouble code, you can reset or clear the Check Engine a number of different ways:

  • You can just drive it and after a certain number of driving cycles it will just clear by itself.
  • Disconnect your battery, turn on the headlight switch for about five to ten minutes, and re-connect the battery. This is pretty simple, but will likely result in you losing your radio presets and perhaps some other small things like that.
  • Most if not all scan tools have an option to clear or reset codes without the use of any tools or touching the battery.

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