P3460 OBD-II Trouble Code: Cylinder 8 Deactivation/Intake Valve Malfunction

Check Engine Light

P3460 code definition

The P3460 code represents what’s known as Cyl8 Deactivation/Intake Valve Ctrl Circ Low. Cyl8 narrows the issue down to engine cylinder number 8. Other codes in the P3400 series may present concurrently with P3460, indicating a problem with another cylinder’s deactivation solenoid.

What the P3460 code means

V8 engines execute a process of deactivating four cylinders when operating under light load conditions, which helps maintain better fuel efficiency. The vehicle only operates on V8 mode during critical events, such as starting, idling, and medium to heavy operating conditions. This switch between modes is lightning fast and imperceptible to the driver. The mass airflow (MAF) sensor, MAP (manifold absolute pressure) sensor, and TP (throttle pressure) sensor are integral parts of the circuit in the cylinder deactivation process. When these sensors don’t send a signal to the ECM within the proper range, the deactivation process is affected and the vehicle will produce a P3400 code, or in the case of cylinder 8, a P3460.

What causes the P3460 code?

The network of components that work together in deactivating the cylinders means that the cause of the code could be the result of a number of issues:

  • Faulty MAP, MAF, or TP sensors
  • Malfunction in the valve lifters
  • Restricted oil pressure
  • Faulty connection in the cylinder deactivation solenoid circuit
  • A solenoid wiring harness short
  • Compromised fuel pressure
  • Mechanical condition of the engine
  • Rarely, a PCM (Powertrain Control Module) fault

What are the symptoms of the P3460 code?

The vehicle will only run in V8 mode, the engine may vibrate while running, and the Service Engine Soon or Check Engine light will likely illuminate.

How does a mechanic diagnose the P3460 code?

The mechanic will make sure the vehicle has proper oil levels and pressure, followed by verifying the Diagnostic Trouble Codes using a scanner, assessing and diagnosing any other codes that are stored in the powertrain control module at the same time. The codes should then be cleared from the scanner. The mechanic will then test the cylinder deactivation solenoid using a scan tool. If the solenoid is malfunctioning, the oil passages will be checked and cleared of debris and other obstructions. If your technician determines that the solenoid is functioning and there are no oil blockages, the valve lifters may be the source of the problem.

Common mistakes when diagnosing the P3460 code

Checking the oil passages for clogs is often overlooked. Checking the oil pressure helps determine whether debris and sludge may be an issue in the deactivation solenoid malfunction, and can help prevent replacing expensive, perfectly functional parts.

How serious is the P3460 code?

A vehicle storing this code may experience compromised fuel efficiency as well as engine vibration. The Check Engine light will likely come on and the vehicle will not be able to operate in V4 mode.

What repairs can fix the P3460 code?

The repair process for a Cylinder 8 deactivation malfunction will depend upon what is found in the diagnostic process, and could include the following:

Additional comments for consideration regarding the P3460 code

The cylinder deactivation process is complex, and involves a network of components each of which should be evaluated in determining the source of the malfunction. If a large amount of buildup is compromising the cylinders’ firing and deactivation processes, the entire engine may need to be taken apart and cleaned out. This is a major task best left to a professional technician. In addition, certain vehicle models may exhibit typical failures, so your mechanic will know what to look at first in that case.

Need help with a P3460 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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