What is VVT Solenoid? | Symptoms of a bad Variable Valve Timing Solenoid

The engine oil plays a big role in the engine’s working. The variable valve timing (VVT) solenoid, also known as an oil control valve (OCV) ensures the proper supply of oil to the engine camshaft and crankshaft. Unfortunately, these VVT solenoids can also fail, which can result in some expensive repairs. This article mainly explains the causes, location, and symptoms of a bad VVT solenoid.

What is a VVT Solenoid?

The variable valve timing (VVT) solenoid is a component of the variable valve timing system that manages the oil flow depending on the engine speed and load. A VVT solenoid in good working condition improves performance and fuel efficiency.

VVT Solenoid

The VVT solenoid or oil control valve can change the amount of oil pressure that gets to the camshaft during times when the car is idling. Lowering this pressure will allow the car to run much better at idle and prevent the oil pressure from getting too high.

The constant use of this solenoid can lead to clogs in the screen that separates the solenoid from the actual VVT pressure switch. The only time you will have any interaction with this part is when it is broken due to the fact that it will not be inspected during routine maintenance.

The most common cause of failure for both the VVT switch and the VVT solenoid is a lack of basic maintenance. If your oil is dirty, sludge can clog the screen on the solenoid, causing a failure. If the engine oil level is low, you will also experience problems with VVT operation.

Working of VV Solenoid

  • The VVT solenoid works with oil pressure, using directions from the ECU to alter the rotation of the camshaft.
  • The solenoid alters the oil flow in the conduit leading to the camshaft phaser(s).
  • Conduits can be “instructed” to hasten or delay intake valve opening depending on which conduit will be called upon by the solenoid.
  • Variation of the intake pressure will be used by the powertrain computer to optimize fuel delivery to the combustion chambers.

Symptoms of a bad VVT Solenoid (Oil Control Valve)

As the oil control valve or VVT solenoid goes bad, it produces one of the below-given sytmpoms:

1) Illuminated Check Engine Light

The latest cars have a powertrain control module (PCM). The PCM monitors and controls the function of your car parts and sensors. As one of these parts start to fail, the PCM will store a specific trouble code that will let a mechanic using a scan tool know that a problem exists. 

The check engine light is one of the most common symptoms of a bad Variable Valve Timing solenoid.

Read More: Causes of Check Engine Light Illumination 

2) Rough Idling

The VVT solenoid adjusts the camshaft timing when your car is running at idle. This is because the idling should be as smooth as possible. A very retarded camshaft timing will make it very difficult for the engine to not drop too low on RPM and stall.

If you notice strange idling problems with your car, it can be because of a faulty VVT solenoid.

3) Rough Acceleration

The main function of the VVT solenoid is to adjust the camshaft timing so you will have effective and smooth engine operation at all different RPMs. If it fails, you may find it causing your acceleration to become rough, and it might even cause misfires when accelerating.

If you have rough acceleration together with a check engine on your dashboard, it could absolutely be due to a faulty VVT valve.

4) Poor Fuel Economy

The purpose of variable valve timing is to ensure that the valves open and close at the right time to maximize engine performance and reduce fuel consumption.

When the VVT solenoid is malfunctioning, the entire system can be compromised, which may result in intake and exhaust valves opening and closing at the wrong time. This typically causes the fuel economy to drastically reduce.

 5) Rattling Noise from the Engine

A faulty VVT solenoid can prevent the VVT actuator from getting the oil pressure it needs. When this happens, you may hear a rattling noise or ticking noise from the engine. Some automakers (e.g., Ford) have technical service bulletins (TSBs) for this concern.

6) PoorEngine Performance

The VVT solenoid was innovated to increase the power on higher RPMs while keeping a steady engine performance at lower RPMs. Therefore, a faulty VVT solenoid can cause the performance to drop a lot if it does not advance the camshaft timing during acceleration.

Causes of a bad or faulty Variable Valve Timing (VVT) Solenoid

Following are the major causes of a bad oil control valve or VVT solenoid:

  1. Dirty oil
  2. Low engine oil

1) Dirty Engine Oil

The VVT solenoid works best when the engine oil is clean, free of debris, or has lost some of its lubricity or viscosity.

When the engine oil valve becomes clogged with debris, dirt, or other foreign particles, it tends to clog up the passageway from the solenoid to the VVT chain and gear. If your engine oil has not been changed out on schedule, it could damage the VVT solenoid, the VVT chain, and the gear drive.

2) Low level of Engine Oil

To avoid this situation, make sure to change your engine oil as recommended by the vehicle manufacturer. Low oil levels can also cause problems with the VVT solenoid and other timing system components.

VVT Solenoid Replacement Cost

The variable valve timing solenoid replacement cost depends on the model of the car, labor cost, and the nature of the repair. The average VVT solenoid replacement cost is between $90 and $510. In this cost, the average labor cost is between $45 to $320, while the part itself costs between $45 to $190.

How To Clean a Variable Valve Timing Solenoid

Follow the below-given steps to clean the oil control valve:

1) Locate the variable valve timing solenoid

The variable valve timing solenoid is usually located around the valve cover. It could be on top of the valve, behind the valve, or on the front side of the valve area.

You can also check the owner’s manual and see the exact location of the VVT solenoid. Make sure that the engine is not hot while you work on it to avoid burning your hands.

2) Disconnect and remove the VVT solenoid

In order to disconnect the variable valve timing solenoid, you need to detach the electrical harness connection by pulling it off simply.

3) Spray it down with mass airflow sensor cleaner

With your gloves and safety goggles on, grab the variable valve timing solenoid and wipe it with a clean towel. Then, spray the solenoid down with the mass airflow sensor.

Make sure that you spray the cleaner in all of the holes. Repeat spraying until no gunk or dirt is coming out. In order to really clean the solenoid well, you will have to connect it to a battery and make it open and close.

4) Let the VVT solenoid dry

Once the variable valve timing solenoid has been cleaned and wiped, you need to let it dry before installing it. The mass airflow sensor cleaner cleans out pretty quickly. However, if you used WD40 or a valve cleaner, you might have to wait a little bit longer.

5) Test the variable valve timing solenoid

After cleaning and drying the variable valve timing solenoid, you should perform a test. You can either manually move it or verify that the solenoid is moving freely. Or, you can test it using two alligator clips and a battery.

6) Reinstall the variable valve timing solenoid

After you verify that the variable valve timing solenoid is working properly, you need to reinstall it. Put the solenoid back in place and reinstall the bolt. Then, reattach the electrical harness.

7) Delete any error codes

A dirty or faulty variable valve timing solenoid can give out many error codes and a check engine light. So, after you are done with the cleaning and have verified that the VVT solenoid works fine, it is time to connect your vehicle to a diagnostic tool and delete the error codes.

FAQ Section

What is the function of VVT Solenoid?

Almost all modern cars use VVT technology to improve their performance and fuel economy. The VVT solenoid helps engines change their valve timing, ensuring that the performance is at its top without losing driveability on lower RPMs.

Electronic principles of electromagnetism in the form of a solenoid valve control the oil flow to the camshafts. The engine control unit sends power and ground to the VVT solenoid when it is time to open the solenoid and adjust the camshaft timing.

Where is Variable Valve Timing Solenoid located?

The VVT solenoid is located at the front of the engine, typically near the front of the valve cover.

How long do VVT solenoids last?

It depends on maintenance and the valve manufacturing quality. It is expected to last normally about 1 to 3 years.

Can I Drive with a Bad VVT Solenoid?

Even though you may technically be able to continue driving with a bad VVT solenoid, the issue can cause damage to additional parts, such as the VVT actuator. So, you should address the issue as soon as possible.

Can VVT solenoid cause low oil pressure?

Most modern VVT systems utilize engine oil (hydraulic) pressure and some type of electronic solenoid to initiate changes in valve timing, lift, and/or duration. One of the most common problems when diagnosing a VVT system malfunction is low oil pressure or engine oil level.

What are the symptoms of a bad oil control valve?

  • Check engine light illumination
  • Rough idling
  • A reduction in fuel economy
  • A clear reduction in the engine performance
  • Rough acceleration
  • Rattling noise from the engine compartment

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