How To Fix Bad Intake Valve Control Solenoid Circuit Bank 1

Last updated on July 16th, 2023 at 10:34 am

The automotive industry has advanced significantly over the past few years. One of the notable advancements in technology is the incorporation of variable valve lift (VVL) and variable valve timing (VVT) systems into modern internal combustion engines.

The variable valve timing solenoid which is also known as intake valve control solenoid circuit bank 1, is what allows adequate amount of oil supplies which makes the engine to be efficient enough and provides great vehicle performance. The VVT is utilized for economizing fuel by making alterations to the valve lift event. 

How To Fix Bad Intake Valve Control Solenoid Circuit Bank 1

Subaru Intake Valve Control Solenoid Location

Over time, you may get an error code which would make you want to find the Subaru intake valve control solenoid. This would happen when the powertrain control module (PCM) finds out that the actual camshaft position doesn’t match the intended camshaft position. It may happen because of an issue with the operation of the VVT solenoid, which may trigger the P0026 code in vehicles that comes with a VVT and/or VVL system.

So the Subaru intake valve control solenoid location can be found on the intake manifold side of the cylinder head, especially on most vehicles.   

What Is The Function Of The Intake Valve Control Solenoid Circuit Bank 1

The function of an Intake Valve Control Solenoid is to use the vehicle oil pressure and an electrical solenoid in controlling the position of the exhaust valve. Note that modern vehicles comes with variable valve timing (VVT).

The VVT system happens to be what helps in adjusting the timing of the opening and closing of an intake and/or exhaust valves which helps in improving the consumption of fuel and/or how the engine performs. This makes use of actuator(s) that are normally mounted on the end of the camshaft(s).

It is the duty of your vehicle’s computer system to send a signal to the VVT solenoid (s) which tells it to apply pressure to the actuator(s) so it can change the position of their corresponding camshaft. When this process is done, it alters the valve timing as needed.

You can turn on the intake valve timing control solenoid valve via the Engine Control Module (ECM) by ON/OFF pulse duty (ratio) signals. Another function of the intake valve timing control solenoid valve is to change the oil amount and direction of its flow via the intake valve timing control unit or stop the oil flow.

This is because the longer pulse width advances valve angle, and the shorter pulse width retards valve angle. So whenever ON and OFF, the pulse widths become equal, and the solenoid valve will stop the oil pressure flow so it can fix the intake valve angle at the control position.

Where Is Subaru VVT Solenoid Location? 

The Subaru VVT solenoid can be found at the front of the engine, normally close to the front of the valve cover. But note that you are not expected to inspect the Subaru VVT solenoid regularly. You can only inspect it when you find the Check Engine light illuminated, or you’re experiencing a problem with the VVT system. Though the vehicle computer system will provide a camshaft position or VVT system related code.

What Is Intake Valve Timing Control Solenoid?

The intake valve timing control solenoid is a component of the variable valve timing system which duty is to manage the flows of oil depending on the load and speed of the engine. When the intake valve timing control solenoid is in good working condition, it improves performance and fuel efficiency. 

The intake valve timing control solenoid is what helps in adjusting the timing of the opening and closing of an intake and/or exhaust valve which helps in improving fuel consumption and engine performance. It utilizes actuator(s) that are normally found on the end of the camshaft(s).

It is the responsibility of the vehicle’s computer system to transmit a signal to the intake valve timing control solenoid which informs it to apply pressure to the actuator(s) so it can change the position of their corresponding camshaft. 

How To Fix Bad Intake Valve Control Solenoid Circuit Bank 1

Whenever the intake valve control solenoid circuit bank 1 becomes bad, there will be an error code. It is this code which is a generic OBD-II powertrain code that will show that there’s an issue. This means that it applies to all makes and models of vehicles. However, specific repair procedures may vary depending on the vehicle’s model. 

Here is how to fix bad intake valve control solenoid circuit bank 1:

Wire harness

Disconnect harness connectors from the PCM/ECM, and this can be done using a wiring diagram by locating the + and – wires to the solenoid. Note that depending on the application, the solenoid can be ground side or power side controlled. You can check your vehicle factory wiring diagrams to know the power flow in the circuit. 

Now make use of a digital volt ohm meter (DVOM) and set it to the volts setting, then find the voltage with the positive lead via the car battery and the negative lead on every wire to the control solenoid. Note that this will depend on the application, when the solenoid is grounded to chassis, then you should test the power lead to the control solenoid at the PCM/ECM wiring harness, and once you do, there should be no voltage present. But if when you find voltage, then check for a short to ground in the wiring up to the control solenoid. This can be done by disconnecting the connectors and working back to the solenoid system.

Control solenoid 

Examine for a short to ground via the control solenoid by putting a digital volt ohm meter lead to a known good ground, while the other to each terminal seen on the control solenoid. Once there’s a low resistance, the solenoid may be shorted internally. 

PCM/ECM

Whenever all the wiring and control solenoid are examined and are certified to be fine, next is to monitor the solenoid while the engine is operating which can be done by back probing the wires at the PCM/ECM. You can also use an advanced scanning tool that will read the engine functions, and use it to monitor the duty cycle commanded to the control solenoid. 

Note that monitoring the solenoid during engine operation should be under various engine RPM’s and load. Make use of an oscilloscope or graphing multimeter to set the duty cycle scale, then you can connect the negative lead to a known good ground and while the positive lead to either wire terminal at the solenoid itself. 

Once done, the reading you’ll find on the multimeter tool should match the commanded duty cycle you’ll see on the scanning tool. But if they are opposite, it means that the polarity may be reversed. Then you can connect the positive lead on the other wire terminal to the solenoid and now re-test it to verify. But if you do not detect any signal from the PCM, then PCM itself may be faulty.

How Long Does It Take To Replace VVT Solenoid?

The variable valve timing solenoid can get faulty over time, and would need replacement. But how long does it take to replace VVT solenoid? This could depend on some car models, sometimes you might end up taking half of the engine apart. However, replacement of the VVT solenoid can be done within 5 minutes. 

What Causes A Variable Valve Timing Solenoid To Go Bad?

The presence of variable valve timing solenoid has increased vehicle performance and fuel efficiency in today’s modern cars. Whenever a car, SUV, or truck is operating in normal driving conditions, it means the variable valve timing solenoid is not active. 

But if the vehicle is operating with extra weight in the trunk, such as pulling a trailer or driving at higher speeds, the VVT system is activated. The variable valve timing switch is the device used to transmit information from the VVT to the vehicle’s computer. 

However, just like every other mechanical or electrical component in your vehicle, the VVT can go completely bad. The common reason VVT will go bad is lack of basic maintenance. When you have dirty or sludge engine oil, it can clog the screen on the VVT solenoid, and this could cause a total failure. 

Another thing that can make the VVT to go bad is if the engine oil level is too low. When your vehicle engine oil becomes too low, you’ll be experiencing problems with VVT operation.

Can You Drive With A Bad VCT Solenoid?

Yes, it is possible to drive with a bad VCT solenoid. Sometimes the vehicle may run with a bad VCT solenoid, but it will likely not run for longer time because of the role the VCT solenoid plays in the timing of the motor. The VCT solenoid in your vehicle is meant to provide easier idling, better power delivery and also in providing better fuel economy. 

For all these to happen, the VCT solenoid requires either advancing or retarding the ignition and fuel timing in the engine to accommodate a specific condition. It is the VCT solenoid system that gets this done easily. It works on the delivery of oil pressure and controls how oil pressure flows. 

But when VCT solenoid fails, it will cause the check engine light to be illuminated in connection with poor engine performance and poor fuel economy. Sometime dirty or contaminated engine oil can cause the VCT solenoid to go bad. So I would recommend you to have a professional mechanic to take a look at your vehicle.

Where Is The Variable Timing Solenoid Located?

The VVT, which is also known as Variable Valve Timing Solenoid is what controls the flow of oil to control what happens on the Sprocket, which shifts the position of the camshaft. However, you can locate the variable valve timing solenoid at the front of the engine. It is normally placed near the front of the valve cover.

How to test variable valve timing solenoid

so, how Do You Test A Variable Valve Timing Solenoid? It is important you test your variable valve timing solenoid to determine if it functions well. I have received lots of email from people asking, how do you test a variable valve timing solenoid?

So here’s how you can test your variable valve timing solenoid with a digital multimeter:

  • The first thing is to ensure you disconnect the electrical connection that is connected to it
  • Then turn the ignition key to the on position. Abut make sure you don’t start the vehicle. 
  • Get the digital multimeter and set it to DC volts. Place the two test leads to the two electrical connections. 
  • Did you see voltage? In case you didn’t see any voltage, then it means you’ll be required to check for shorts and the wiring.

Conclusion

As you can see, the variable valve timing or VVT as it is called is one of the most noticeable breakthroughs in the history of automotive industry. Most of the modern cars in the market come with variable valve timing (VVT) systems, which is used to improve fuel economy and performance by altering the valve lift event. The VVT is what allows the correct amount of oil supply, it allows the engine to provide great fuel efficiency and performance. 

But like every other engine component, the VVT solenoid may over time fail. This component needs to be well lubricated, and whenever the intake valve control solenoid is not lubricated properly, it will cause lots of disruption and may cause damage to the timing chain and the gear. The P0026 Code is one of several diagnostic error codes that may show to indicate that there’s a problem in the operation of the systems.

The P0026 error code can be fixed, and I have been able to show you steps to take in having it cleared. But if you are unable to clear it, then you can contact a professional to help.

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