Symptoms of a Bad VVT Solenoid: What You Need to Know

The symptoms of a bad VVT (variable valve timing) solenoid can vary greatly. How they present for you will depend on the make and model of your vehicle, as well as the extent of the part’s failure. Some vehicles may produce unusual sounds, while in other cases, the signs are so subtle they’re barely noticeable.

Read on to learn more about the warning signs that point to a bad VVT solenoid to help you accurately diagnose your vehicle.

What are the Signs of a Bad VVT Solenoid?

VVT solenoid issues are often linked to oil sludge buildup in the solenoid, usually caused by frequent short trips with a cold engine or extended oil change intervals. But in general, the signs of a bad VVT solenoid include the following:

Reduced Fuel Efficiency

It can be confusing when your fuel-efficient car suddenly consumes more fuel than it used to. This can be caused by a bad VVT solenoid, which can cause mistimed valve events.

Check Engine Light is On

One of the most common signs is an illuminated check engine light and a stored “P00xx” trouble code (such as P0010, P0011, and so on). The code may be a “performance” code, which indicates that the VVT solenoid is electrically sound but that the camshaft doesn’t respond as expected when the VVT is activated.

Keep in mind that there is a wide range of problems that can trigger the Check Engine light and the previously mentioned codes. Either way, when this happens, make sure to get your car checked before the issue worsens.

Unusual Sounds Coming From the Engine

What does a bad VVT solenoid sound like? There is no exact answer. Some people hear a light vibration or tapping noise that almost blends in with the engine’s normal hum. Others may hear loud thumps (that can be quite alarming to hear) caused by the valve becoming erratic.

Engine Performance Issues

Hesitation and surging can occur with a faulty VVT solenoid. When the engine’s timing is off due to a bad solenoid, overall drivability may be affected. Misfires and surges can indicate a VVT problem but will require specific troubleshooting to confirm.

Rough idling

Unusual shaking and other inconsistencies while the vehicle is idling can also occur. These issues often happen when the faulty component allows too much oil to flow through the VVT system.

What Causes a VVT Solenoid to Go Bad?

This component is constantly moving as long as the engine is on, making it prone to wear over time. But it can also fail or sustain damage prematurely, thanks to the following:

• Contaminants in the engine’s oil
• Frequent short trips that form sludge in the oil system
• Electrical failures in the VVT solenoid or its circuit

Failure of other parts in the valve timing system could also cause or contribute to these factors. But sometimes, these solenoids simply give out because they are defective or subpar.

What Does a VVT Solenoid Do?

Valve timing is crucial whether or not an engine has Variable Valve Timing (VVT). In a non-VVT engine, the crankshaft and camshaft are either in sync or out of sync. In VVT engines, however, valve timing is adjusted dynamically by engine control algorithms through an oil control solenoid.

The first VVT system in an American car appeared in the 1995 Ford Contour, which featured a Mazda engine with oil-adjusted helical-cut gears built into the exhaust camshaft gear. When the VVT solenoid opened to allow oil pressure to shift the alignment between the inner and outer gears, it slightly advanced the exhaust valve timing while driving.

In that design, advancing the exhaust camshaft caused the exhaust valves to close earlier, trapping some exhaust gas in the combustion chamber and eliminating the need for an EGR system.

Since then, VVT has been incorporated into many engines to improve performance and emissions. Modern VVT systems use a solenoid to direct oil pressure to one side of a set of vanes within the cam gear(s), adjusting the relationship between the gear and the camshaft. This adjustment is done precisely, with the camshaft sensor providing feedback.

What is Variable Valve Timing or VVT?

Car engines use valves to manage the airflow in and out of the engine, enabling the combustion process. The VVT system manages this process by indicating the timing for opening and closing valves according to what the vehicle needs and how it runs. Typically, the VVT is in a state of flux as it sends oil pressure to the cam gear actuator. Each actuator will have its own VVT solenoid matching the engine’s variable valve timing.

Where is the VVT Solenoid Located?

Vehicles of different makes and models can have different locations for these systems. Still, the usual location of the VVT solenoid is somewhere around the front of the engine, often near the valve cover or, as on the 2.4L Camry engine, on the back side of the engine and out of sight.

VVT Solenoid Replacement Cost

Many factors can affect pricing for the replacement part and labor, so the total amount for replacement could vary. The cost of a replacement VVT solenoid will typically depend on the vehicle’s year, make, and model. As expected, parts for luxury vehicles tend to be more expensive. Prices range from under $5 to more than $1,500 a piece.

Meanwhile, the average price for labor when replacing this part ranges between $133 to $170. Keep in mind that how much you would end up paying could also vary based on how severe the issue is and the complexity of the repair.