Home / OBD Codes / P0028 OBD-II Trouble Code: Out of Range Performance of Intake Valve Control Solenoid Circuit Bank 2

P0028 OBD-II Trouble Code: Out of Range Performance of Intake Valve Control Solenoid Circuit Bank 2

The Definition of Trouble Code P0028

Out of Range Performance Detected for the Intake Valve Control Solenoid Circuit Bank 2

If your vehicle is equipped with variable valve timing, then the component that controls the camshafts is the hydraulic actuator. The actuator is fed by the engine oil system using the control solenoids which in turn is controlled by the Powertrain Control Module (PCM). This trouble code can arise when the PCM is detecting an out-of-range movement from the Bank 2 intake camshaft when the vehicle is being operated. The movement has to be out of the threshold from operating specifications. In this case, Bank 2 means that the problem might be from the opposite side of cylinder #1. But you will need to verify this according to the manufacturer’s specification of your vehicle. Generally, the control solenoid it’s usually located on the same side of the intake manifold.

Note: The occurrence of this code might also be related to the other fault codes, including P0081, P0082, or P0083. But, even when these codes appear, you might need to fix the solenoid circuit before moving on to the solution steps for other trouble codes. This code is also similar to trouble codes of P0026, P0027, and P0029.

P0028 OBD II Trouble Code

What Does Trouble Code P0028 Mean?

P0028 is the OBD-II trouble that might occur when the Engine Control Module of your car has detected that the valve lift mechanism of the intake valve bank 2 does not work properly.

What are the Causes of Trouble Code P0028?

  • The valve lift mechanism cannot be activated, even after the intake valve solenoid is initialized by the ECM.
  • There is a short-circuit or open circuit on the component of intake valve solenoid bank 2.
  • There is a short or open circuit on the connection or wiring between the valve lift solenoid and ECM.
  • There might be some oil or dirt deposit on the connector or wiring of the valve lift solenoid.

The Symptoms of Trouble Code P0028

  • The driver can notice the lack of power from the engine when the valve lift mechanism fails to engage, and the optimal operation is not possible.
  • The vehicle is experiencing stalling or running rough.
  • The vehicle has difficulty accelerating.
  • The dashboard has the Check Engine Light illuminated.

How Your Mechanics Diagnosed the Trouble Code P0028

  • They should check the condition of the wiring and connections related to the intake valve solenoid.
  • They should check and clear the trouble code on the PCM before testing the system again to verify the occurrence of the problem.
  • They should test the solenoid circuit to see if the valves mechanism can work and change from low to high lift.
  • They should always follow the manufacturer’s manual before doing any further diagnosis.

Some Mistakes in The Process of Diagnosing Trouble Code P0028

Below are the simple guidelines to prevent mistakes when trying to diagnose trouble code P0028:

  • Clearing the trouble code first before verifying the failure and see if it still persists.
  • Always use a test solenoid as a special tool to do the diagnosis.
  • Isolate the failure to make sure that the problem is not caused by other components.
  • Replace parts that are needed for the problem that is related to the intake valve solenoid.

How Serious Is Trouble Code P0028?

  • Your vehicle might run rough or might even stop suddenly.
  • Your vehicle might have difficulty when you’re trying to accelerate from low speed.
  • Your vehicle might have a hard time starting or run too lean.

How to Repair Trouble Code P0028?

  • Verify the root of the problem and replace the valve lift solenoid if the component is the one that causes the problem code.
  • Replace the clogged passage in the solenoid circuit after verifying if the valve lift mechanism can shift properly.
  • Replace any damaged wiring and connection that are related to the valve lift solenoid.
  • Replace the ECM or the connector if the problem is caused by the component.

Engine oil – You need to make sure that the engine oil capacity is enough for the component to work properly. This is because the actuators will work by using the oil pressure, and they will not reach optimal conditions without the proper amount of oil in the engine. You should also check if the fluid is dirty or contaminated because it might cause build-up that can lead to the failure of the valve solenoid or the actuator itself.

Control solenoid – You can use a Digital Volt/Ohm Meter (DVOM) to check the condition of the control solenoid for the camshaft. You should check the continuity by unplugging the solenoid harness first before checking the resistance. The checking process can be done by connecting the positive and the negative leads of the DVOM to each terminal on the solenoid. You can then inspect the internal resistance number to see if the number is within the threshold from the manufacturers. If the number is correct and within specifications, then it means that the control solenoid is not contaminated. But you can also use this process to see if there’s a lack of oil pressure due to the damage to the sealing.

Subaru Intake Valve Control Solenoids

Camshaft activated – The actuator is a mechanical device that is controlled by the pressure on the internal spring and is adjusted by the pressure of oil that is controlled by the solenoid. This component will always return to its default safe position when there’s no oil pressure supplied on. You should always refer to the manuals on the procedures of how to remove the actuator from the camshaft. This is to make sure that there will be no leaks that can cause a loss of oil pressure to the connection of the actuator. You should also check the timing chain and the components around it to make sure that everything is working in the correct order.

ECM/PCM – The ECM/PCM is a component that will control the solenoid by sending pulse width modulated signals which will regulate the control of the actuator pressure. You will need a graphic multimeter to see the PWM signal if you want to maintain a proper operation of the ECM/PCM. You can do this by connecting the positive lead to the ground side of the solenoid. Meanwhile, the negative lead should be attached to a known ground terminal that is in a good condition. You can then check the number to see if the PWM signal is consistent with the RPM changes. If not, then it is an indication that there is a problem with the ECM/PCM.

Additional Comments Related to the Occurrence of Trouble Code P0028

The intake lift solenoid is the component that will actuate the mechanism for the valve intake lift. It does this by opening and closing the oil pressure to the valve lift mechanism. As a result, the valve lift will shift from low to high on the camshaft.

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