P3427 OBD-II Trouble Code: Cylinder 4 Deactivation/Intake Valve Control Circuit Low

What the P3427 code means

When starting, and when the vehicle is operating under heavy weight, the engine will operate in V8 mode. But when driving conditions are light, the engine will deactivate 4 of the 8 cylinders, thereby changing from V8 to V4 mode. Using information it receives from the mass airflow sensor, your vehicle will determine the proper driving conditions.

The PCM will then instruct the cylinder deactivation solenoids and this will start the cylinder deactivation process. The cylinder deactivation solenoids will deactivate cylinder 1, cylinder 4, cylinder 6, and cylinder 7, and it does this by restricting the flow of oil to the valve lifters for these cylinders, and then preventing the intake valves and exhaust valves from opening.

When the PCM detects that the measured values of the mass airflow sensor, the intake control manifold absolute pressure sensor, and the throttle position sensor are not within the range for V4 mode, then it will store the P3427 diagnostic trouble code.

What causes the P3427 code?

There may be one or more causes for the P3427 code:

• Defective cylinder deactivation solenoid

• An open or short in the cylinder deactivation solenoid harness

• Poor oil pressure on the lifters

• Defective lifters

• Defective throttle position sensor

• Defective intake control manifold absolute pressure sensor

• Defective mass airflow sensor

• Clogged or restricted oil passages

• Low oil level in your engine

• A poor electrical connection in the cylinder deactivation solenoid circuit

What are the symptoms of the P3427 code?

Some symptoms include a vibrating engine and a check engine light that will not turn off.

How does a mechanic diagnose the P3427 code?

The first thing you should do is make sure that your engine oil levels and oil pressure are correct. Use your OBD-II scanner to collect all diagnostic trouble codes stored by the powertrain control module (PCM). Remember that if the powertrain control module (PCM) has stored other deactivation or oil pressure trouble codes, these should be dealt with first. Clear the trouble codes with your OBD-II scanner, and then test the cylinder deactivation solenoid #1 by actuating the cylinder with a scan tool.

A solenoid that is in good shape will vibrate and make a small clicking noise. If the cylinder deactivation solenoid #1 is working incorrectly or not at all, check your oil passages for debris and clean those oil passages if you feel they should be cleaned. Afterward, replace the solenoid.

Common mistakes when diagnosing the P3427 code

One common mistake is not checking the oil passageways for dirt and sludge. Clogged oil passageways can diminish engine oil pressure and prevent the cylinder deactivation solenoids and lifters from operating as they should when switching from V4 to V8 mode. Always be sure to check the oil passageways carefully to make sure that you are properly diagnosing the problem.

How serious is the P3427 code?

Because the vehicle will operate only on four cylinders instead of eight, this should be attended to immediately. This will cause an increase in engine emissions and a loss of fuel economy. Although a P3427 code is not as serious as some others, you should attend to it quickly, as over time it could produce irreversible effects.

What repairs can fix the P3427 code?

Several repairs can be done for a P3427 code. It depends on the exact issue that your vehicle is having. One thing you might do is replace your cylinder deactivation solenoid #1. You might also replace your cylinder deactivation solenoid #7 or clear your cylinder deactivation solenoid oil passages of dirt and debris. You could also clear your lifter oil passages of dirt and debris or replace the lifters in your engine. If your entire engine is clogged with sludge and dirt, you may need to disassemble the engine and clean it carefully.

Additional comments for consideration regarding the P3427 code

This code can become complicated and may require that you disassemble the entire engine to repair the problem correctly. This may become a complex and involved task, even for the most experienced technician so it is important to do the proper amount of research before you take your engine apart.

Need help with a P3427 code?

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