Variable Timing Solenoid

• A variable valve timing solenoid, also known as a VVT solenoid, is an oil-pressurized component of the VVT system that alters the timing of an engine’s valve lift event.
• The engine computer sends signals to a specific VVT solenoid, sending oil to lubricate the timing chain and gear that controls camshaft rotation.
• A VVT solenoid allows the vehicle to control and maximize the overlap of the intake and exhaust valve’s opening for better engine performance.
• The VVT system may advance or delay the opening of intake and exhaust valves to support activities that put an additional load on the engine such as carrying heavy payloads or driving uphill.
• The cost of a variable valve timing solenoid will vary depending on your vehicle’s specific year, make, and model. In general, OE replacement parts cost in the range of $2 to $613. They are sold individually, in sets of two or four, or as part of a complete kit.
• A functioning variable valve timing solenoid is critical to maintaining engine health. Like all mechanical components of your vehicle, they may wear out or get damaged over time.
• Signs of a bad or a failing variable valve timing solenoid include the activation of the Check Engine Light, rough idling, and reduced fuel economy.
• This part typically fails due to problems concerning engine oil viscosity or contamination. Blockage in the passageways can result in the solenoid getting damaged, while the timing chain and gears may break down as a result of poor lubrication.

Back in the day, an engine’s intake and exhaust valves automatically opened and closed at specific points and intervals during the four-stroke cycle. Today, most modern vehicles have engines that are equipped with variable valve timing (VVT) technology that allows them to control when and for how long these valves remain open, maximizing the overlap of the intake and exhaust valve’s opening for better engine performance.

A variable valve timing solenoid, also known as a VVT solenoid, is an oil-pressurized component of the VVT system that alters the timing of an engine’s valve lift event. This part helps the system ensure that enough power is produced to support the demands of changing engine speed and load.  Each camshaft has a variable timing solenoid that contributes to better engine performance, improved fuel economy, and lower emissions.

An engine variable timing solenoid is a component of the VVT system that alters the camshaft position by managing oil flow, depending on engine speed and load. Each solenoid receives electromagnetic signals from the engine computer and is powered by a low current from the car battery.

The engine computer sends signals to a specific VVT solenoid, sending oil to lubricate the timing chain and gear that controls camshaft rotation. As a result, the VVT system may advance or delay the opening of intake and exhaust valves to support activities that put an additional load on the engine, such as carrying heavy payloads or driving uphill.

Valve timing covers the time when the intake and exhaust valves open, how long they stay open, and when they slam shut. The timing affects engine horsepower and torque at any given revolutions per minute (RPM).

In older vehicles, the gears of the camshaft and crankshaft set the valve timing of the engine. The two shafts bear timing marks that align in a specific pattern called the cam profile.

Cam profiles behave differently depending on the engine’s RPM. Some profiles generate plenty of power at low engine turning speeds, while others need lots of revolutions to hit their best performance.

The engines on earlier vehicles featured fixed cam drives with unchangeable valve timing. Most cars had cam profiles suited for low-to-medium levels of torque. They proved very efficient for daily driving but did not do well at the higher loads required for, say, going uphill.

Before the first variable valve timing system, it was possible to adjust valve timing so that the engine worked better at the opposite end of the torque spectrum. But it required tinkering with the drive gear on the camshaft and sacrificed the engine’s performance in its normal range.

A VVT system is an electronic system that actively changes the valve lift event. For example, it may cause the valves to open and close later than usual. By tweaking the timing of the intake and exhaust valves, the VVT system can adjust the cam profile of the engine.

Most variable valve timing systems place a camshaft actuator on the cam drive gear. Also called a “cam phaser” or simply “phaser,” the actuator changes the profile of the cams, increasing the engine’s efficiency at higher RPMs.

These systems also have a valve timing solenoid. The electronic device controls the oil flow control valve that supplies the cam phaser with engine oil.

A functioning variable valve timing solenoid is critical to maintaining engine health. Like all mechanical components of your vehicle, they may wear out or get damaged over time. Here are some of the symptoms you should look out for, to prevent a failing VVT solenoid from causing complete engine failure.

Check Engine Light is switched on or blinking

Most modern engines have an engine control unit (ECU) that monitors the performance of individual components. This computer conducts several tests that allow it to check for any problems with the engine and its related components. When a fault is detected in the system, it logs a trouble code and triggers the Check Engine Light to illuminate.

How to test a variable valve timing solenoid

There are about a dozen on-board diagnostic trouble codes that can be linked to a faulty variable valve timing solenoid. To accurately diagnose your vehicle, you’ll need to use an OBD-II scan tool and connect it to your engine computer to retrieve the exact engine trouble code.

While this will help pinpoint the location of the problem, there is still a long list of possible triggers for each engine code. Once you have this information, it’s best to seek the help of a licensed mechanic to accurately determine whether or not your vehicle’s variable valve timing solenoid needs to be replaced.

Reduced fuel economy

A malfunctioning variable valve timing solenoid will reduce your engine’s ability to maximize the overlap between the opening of the intake and exhaust valves, increasing your fuel consumption to support the same engine load. If you notice that you’re needing to fill up your tank more often than usual, this may be a sign of a failing variable valve timing solenoid.

Rough idling

A problem in the VVT system can cause the variable valve solenoid to activate the opening of the intake valves even if the vehicle is driving at a low speed and is not under heavy load. This will cause the engine’s RPM to fluctuate and contribute to premature wear on engine components.

A faulty variable valve timing solenoid is often caused by failure to change the engine oil on time. Problems typically arise when the oil becomes too thick or too thin, affecting the VVT system’s operation. Contamination from debris and other foreign particles can also clog up the system and damage, not just the variable timing solenoid, but also other components such as the timing chain and gear drive due to lack of lubrication.

Due to the location of the VVT solenoid on the camshaft, this part isn’t typically checked during regular maintenance. It’s important to have it checked and tested by a professional mechanic as soon as your engine computer triggers a VVT system-related trouble code to prevent poor engine performance and increased emissions.

The cost of a variable valve timing solenoid will vary depending on your vehicle’s specific year, make, and model. In general, OE replacement parts cost in the range of $2 to $613. They are sold individually, in sets of two or four, or as part of a complete kit.

Is your vehicle not getting power from the engine the way it used to? Do you also notice higher fuel consumption? It is time to change your variable timing solenoid! The solenoid is close to the variable valve timing switch at the camshaft; this location makes it challenging to inspect the solenoid regularly. We recommend that you examine it when the Check Engine light is on or when you suspect that your variable valve timing system has been causing issues in your vehicle. And when it does need replacement, here are the step-by-step instructions to guide you:

Difficulty level: Moderate

Things you'll need:

• Wrench
• Scan tool
• Long torx screwdriver

Step 1: Locate and identify the defective variable valve timing solenoid.

Step 2: Remove the bolt that keeps the air intake tube in place and take the tube out.

Step 3: Remove the nut that attaches the power steering bracket to the cylinder head. At the bottom of the power steering bracket, loosen the bolts that attach the bracket to the engine block.

Note: You do not have to completely remove the bolts. Just loosen them enough so that the power steering bracket can slide out.

Step 4: Remove the bolts that hold the power steering reservoir. Take the power steering reservoir bracket out of your vehicle as well.

Note: You just have to lean the reservoir against the fender; no need to remove or empty the reservoir.

Step 5: Press the tab on the valve timing solenoid and pull it up to unplug the electrical connector from the valve timing solenoid.

Step 6: Remove the variable valve timing seal from the valve cover.

Step 7: Use a long torx screwdriver to loosen the bolt that keeps the variable valve timing solenoid firmly in place. While doing it, pull the solenoid carefully. It should come out while you loosen the bolt.

Note: Keep just the right amount of pressure on the torx screwdriver against the bolt to keep the bolt from falling inside the engine bay.

Step 8: Install the new solenoid. Place the bolts on it. Keep the pressure on the bolt while sliding the solenoid slowly in place. Tighten the bolt.

Step 9: Clean and mount the valve cover and the variable valve timing system. Put a thin coat of oil on the inner portion of the valve timing seal so that it will not get torn when you install it. Lubricate the area of the solenoid that goes inside the engine.

Step 10: Mount back the components you removed in the reverse order you dismounted them.

Step 11: To check if the new solenoid will work properly in your variable valve timing system, test the engine using a scan tool. If the scan tool does not show any trouble code, then you can rest assured that the new solenoid will function well. Otherwise, you will have to replace it with another solenoid that fits your particular vehicle's variable valve timing system.

Step 12: Take your vehicle for a road test to ensure that your variable valve timing system is working well now that it has a new solenoid. You should be able to feel a big difference in the ride's responsiveness—there should be no backfiring and rough idling.