Common Symptoms of a Bad Variable Valve Timing Solenoid and How to Test It?

Hi readers! I hope you are doing well and exploring new things daily. A bad VVT solenoid will defeat a strong engine and turn it into a weak fuel-burning machine, catch the signs before it is too late. Today we will discuss the symptoms of a bad variable valve timing solenoid and how to test it.

Variable Valve Timing (VVT) solenoid is vital to modern internal combustion engines aimed at performance, fuel economy, and emissions improvement. It manages oil flow to the VVT system, which alters valve timing, namely intake and exhaust, to be highly precise. Optimizing timing thus allows the VVT solenoid to offer a smooth engine feel under various driving conditions while coupling with additional power and fuel economy.

With a faulty VVT solenoid, the engine may undergo performance problems. Common symptoms include rough idling, hesitation during acceleration, and a notable power drop. Such being the case, any solenoid that is no longer good will tend to increase fuel consumption since the engine will always try to adjust for peak combustion efficiency. The check engine light is another thing that comes on when improper adjustments on the valve timing are observed.

For the worst, misfires may follow soon after, leading to higher emissions if left unchecked. In very extreme conditions, engine failure will occur due to poor combustion and excessive wear of engine components. Good maintenance practices, which include timely oil changes and regular VVT solenoid checks, will prevent the above problems from arising and help maximize engine efficiency and reliability in the long run. Early indications are just enough to safeguard repairs and prevent the car from running into problems.

This article attempts to expose the symptoms common to any failing VVT solenoid, the reasons that may cause VVT solenoid failure, and the stepwise process of testing to find out the failing component. Let’s dive.

What are the symptoms of a bad VVT solenoid

The Variable Valve Timing (VVT) solenoid-on-demand component is one of the nerve centers in modern internal combustion engines' strategy implementation for improving fuel efficiency, emissions control, and lowering power output. Yet, when one fails, the VVT solenoid will create real havoc in performance issues affecting drivability and overall engine health.

Thus, it is important to know the very early warning signs of a failing VVT solenoid. It may just be possible to prevent expensive repairs or engine damage. In summary, in the following post, the most common symptoms of a bad VVT solenoid are broken down in detail.

1. Check Engine Light (CEL) is on:

One of the first and most common signs of a malfunctioning VVT solenoid is the check engine light coming on in the dashboard. The ECM continuously monitors the VVT system and lights the check engine if any irregularities are detected, correlating to valve timing adjustments.
Once the light has been illuminated, an OBD-II scanner facilitates the lookup of specific diagnostic trouble codes (DTCs) regarding the VVT solenoid. Some commonly reported codes include:

P0010 - Intake Camshaft Position Actuator Circuit (Bank 1)
P0011 - Intake Camshaft Timing Over-Advanced (Bank 1)
P0012 - Intake Camshaft Timing Over-Retarded (Bank 1)
P0020 - Exhaust Camshaft Position Actuator Circuit (Bank 2)
P0021 - Exhaust Camshaft Timing Over-Advanced (Bank 2)
P0022 - Exhaust Camshaft Timing Over-Retarded (Bank 2)

If one of these codes pops, then you should continue to inspect the VVT solenoid along with its components.

2. Rough Idling and Stalling Engine:

The VVT solenoid serves to control the flow of oil to the camshaft phaser, and it malfunctions. This not only changes the 'tuning' of the valve timing but also causes failures in terms of air pulses in the combustion chamber.

This may be manifest in the form of the engine: 

●Idling roughly with perceptible vibrations. 
●Fluctuation in RPM with the vehicle still. 
●Stalling suddenly on stopping or shifting to gear. 
In more severe cases, a defective VVT solenoid may bring about an engine stall.
A rough idle and stalling of an engine would result from a malfunctioning VVT solenoid. As the engine is kept idle, it may excessively shake, or, even worse, it may not be able to keep a steady RPM.

3. Weak Power and Poor Acceleration:

Without the proper functioning of the VVT solenoid, the engine would hardly produce a power output ranging from "GGUUUUUUUH," especially when there's much acceleration. Its function is to modify the timing via adjusting the camshaft, allowing it to be used with the most power across a varying engine speed.
It will generally cause the following moods of a driver:

●Delay in meter reading under throttle response. 
●Weakness in accelerating, which makes overtaking almost impossible. 
●"jerky" sensations when gas is pressed or sometimes even hesitates to respond.

4. Reduced Fuel Efficiency:

A failing VVT solenoid can result in reduced fuel efficiency. The VVT system serves the purpose of enhancing fuel consumption optimization through valve lift advancement or delay in the timing of the intake and exhaust valves. Failure of oil supply regulation may prevent the adjustment of the camshaft to attain the best position of operation leading to an engine with poor fuel economy.
Some of the symptoms indicating reduced fuel economy include:

●You drive to the gas station more often than you used to.
●A dip in your miles per gallon (MPG).
●Increased fuel bills despite normal driving. 

A defective VVT solenoid would make the engine burn more fuel to account for its inefficiency in valve timing as compared to the altered pace of the device. The issue, however, can be addressed early to get the intended fuel efficiency and reduce costs in operations.

5. Engine Misfires And Hesitation:

The changes in pressure affect the burn and create an incomplete combustion process due to a mismatched air-fuel ratio or timing. Misfires of the engine might be the result of a malfunctioning VVT solenoid, which occurs mainly when the engine is on load as it requires exact timing.

Symptoms of engine misfires are:

●Tendency of jerks while driving
●Strange tapping or popping noises from the engine
●Hesitation at acceleration
●General reduction in engine performance

Misfires also lead to much more damage over the long term to the components such as spark plugs, ignition coils, and the catalytic converter. Tolerance of the issue proves to be quite costly and decreases the lifespan of the engine.

6. Increasing Emissions and Failing Emission Tests:

Malfunctioning VVT solenoids leads to incomplete combustion, thus increasing emissions. When valve timings are not properly set, the unburnt fuel passes as emissions through the exhaust system, increasing hydrocarbon (HC) and nitrogen oxide (NOx) emissions.
Some of the increased emissions concerns are:

●falling the state-imposed emission tests
●The dark exhaust smoke
●The exhaust pipe gives off a strong fuel odor

If the vehicle fails an emissions test, everything important should be prioritized to inspecting the VVT solenoid and the associated components.

7. Unusual Engine Noises:

A defective solenoid will thus make unusual sounds with the engine since the camshafts may not be adjustable. An improper oil flow regulation leads to the non-smooth operation of the camshaft phaser, which will, in return, produce tick or rattling noises.

Common noise for a bad VVT solenoid includes the following:
●Sounds of rattling or ticking coming from the engine, particularly at idle
●Knocking sounds while accelerating or decelerating
●The valvetrain was noisy so he would know that incorrect timing adjustments had been made.
All these sounds indicate that the solenoid is stuck or cannot regulate oil pressure properly.

8. Contamination as well as clogging of oil by a Solenoid:

A VVT solenoid functions on the principle that clean engine oil must be present in the engine. The oil that is dirt or contaminated will make the solenoid clogged, which will limit the oil supply to the cam phaser.

Signs of VVT solenoid failure regarding oil-related aspects include:
●There is sludge build-up around the solenoid.
●Contaminated oil when checked on the dipstick.
●A delayed response from the engine when accelerating. 
Regular oil changes and high-quality oil can prevent these issues and extend the lifespan of the VVT solenoid.

Related Reading: Decoding Your Car's Check Engine Light

How to Test a VVT Solenoid

If you suspect it is not working, you can do the tests below that will confirm if it still needs to be repaired or needs replacement. Broken Variable Valve Timing or VVT solenoids may cause performance issues like rough idling, lousy acceleration, and increased fuel consumption. Listed below are four methods to efficiently test a VVT solenoid to determine whether or not a diagnosis needs to be made.

1. Check for Trouble Codes with an OBD-II Scanner:

When diagnosing faulty Variable Valve Timing solenoids using an OBD - II scanner, tools like the ANCEL AD310 can quickly retrieve Diagnostic Trouble Codes (DTCs) related to valve timing issues. 

Steps:
 

• Find the OBD-II port, which is located in almost every vehicle under the dashboard near the seat of the driver.
• Plug in the OBD-II scanner and turn the ignition to "ON" without starting the engine.
• Following the scanner interface, read the codes being stored.
• Then, look for a specific VVT-related code, such as:
  -P0010 – Intake Camshaft Position Actuator Circuit (Bank 1)
  -P0011 – Intake Camshaft Timing Over-Advanced (Bank 1)
  -P0020 – Exhaust Camshaft Position Actuator Circuit (Bank 2)
• Then, a suggestion of which issue has existed with the VVT solenoid or possibly some components relating to it is that such a code is present: More tests will be necessary.

2. Visual Inspection:
Very simple: taking a simple look will show external damage, contamination, or wiring issues that are making the VVT solenoid not work.
Steps:

• Identify the location of the VVT solenoid; it is usually mounted close to the camshaft on the engine.
• Check the solenoid for oil leakage because too much oil suggests seal failure.
• Corrosion, loose connections, or damaged wires may occur on the electrical connector.
• Dirt or sludge will be visible all over the solenoid, blocking the oil to causing improper operation.
• For any existing dirt, the cleaning method used would be with non-abrasive cloths and appropriate cleaners.

In this case, it must be replaced if there is visible damage, corrosion, or even leaks.

3. Perform a test of the VVT Solenoid with a Multimeter:
The VVT solenoid can be checked with the help of a multimeter measuring its electrical resistance.
Steps:
 

• Put the multimeter in resistance mode (Ohms, Ω).
• Remove the electrical connector from the VVT solenoid.
• Place multimeter probes on the solenoid terminals.
• Observe resistance reading. The resistance of a good healthy VVT solenoid usually falls between 5 and 25 ohms; please refer to your vehicle's service manual for exact specifications.
• Out-of-range (too high or too low), or even showing infinite resistance, might be indicators that it is defective and needs replacement.

4. Subject to Applying a 12-volt Direct Power Test:
Directly applying a source of supply at 12V would tell if the VVT solenoid indeed engages properly.
Steps:
 

• Remove the VVT solenoid from the engine.
• Connect another set of jumper wires between the solenoid terminals and the battery.
• When power jumps in, there should be a clicking sound indicating that opening and closing occur at the time.
• Otherwise, if no clicking occurs, or the power is applied but no response comes from it, it could be considered faulty.

Conclusion

Faulty VVT solenoids can practically cause symptoms in the faulty condition of an engine, including rough idle, poor acceleration, poor fuel economy, and higher emissions. Early recognition of such symptoms can help curb bigger repair expenses and increase assurance of the read performance of the engine.
After scanning for error codes with an OBD-II scanner, followed by a visual inspection and testing the electrical resistance of the solenoid with a multimeter, you can determine whether the VVT solenoid is indeed defective. If the solenoid fails either of the tests, it must be replaced to attain the proper function of the engine.

Defective VVT solenoid maintenance with regular oil services at the right intervals and checking these will assist in prolonging their lifespan and not falling to premature failures. The state of the solenoid and the oil passage will maintain efficient valve timing and overall engine conditions.