P2647 Code: “A” Rocker Arm Actuator System Stuck On Bank 1

There are many diagnostic trouble codes (DTCs), one of which is P2647. P2647 is a diagnostic trouble code (DTC) for “System Too Rich (Bank 1)”. This can happen for multiple reasons, and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. This article explains the causes and symptoms of the P2647 code.

P2647 Code Definition

Diagnostic trouble code (DTC) P2647 represents “‘A’ Rocker Arm Actuator System Stuck on Bank 1.”

What does the P2647 Code Mean?

The P2647 code indicates that the powertrain control module (PCM) has detected a malfunction in the intake camshaft rocker arm actuator system (A). This code is most commonly found on Honda and Acura vehicles equipped with Variable Valve Timing & Lift Electronic Control (VTEC). 

P2647 Code

Engines with VTEC use a rocker arm actuator system to vary engine valve lift. A typical system has two camshaft profiles: one for high RPM and one for low RPM. 

When the engine reaches a predetermined speed, the powertrain control module (PCM) operates a solenoid valve that allows oil pressure to activate a pin assembly that locks the rocker arms together, forcing them to follow the high RPM camshaft profile.

The PCM monitors the oil pressure switch to verify the change has occurred. The P2647 code may show up if the actual state of the oil pressure switch is not what the PCM expects.

Symptoms of the P2647 Code

Following are the most common symptoms of the P2647 code:

  1. Illuminated check engine light
  2. Vehicle runs rough
  3. Poor fuel economy
  4. Poor engine performance
  5. Misfiring during acceleration

Read More: Symptoms and Causes of P2646

P2647 Code Causes

Many issues can cause the P2647 code to trigger. Following are the most common causes:

  1. Faulty VTEC oil pressure switch 
  2. Clogged oil passages 
  3. Low engine oil level
  4. Obstructed oil screen 
  5. Bad VTEC solenoid 
  6. Wiring problems, such as damaged wires and poor connections 
  7. Low oil pressure 
  8. The faulty powertrain control module

Read More: Causes of Check Engine Light Illumination 

Common P2647 Code Diagnostic Mistakes

The following are the most common mistakes that a technician may make when diagnosing a P2647 code:

  • Not diagnosing the root cause, which could be low oil pressure
  • Not checking the wiring or harnesses for damage or disconnections
  • Not checking the freeze frame data
  • Replacing parts that do not fix the problem

How to fix the P2647 Code?

  1. First of all, check the engine oil level and oil pressure.
  2. Test the variable valve timing parts to ensure their proper function.
  3. Conduct a visual inspection of all connections and wiring.
  4. Test all circuitry related to the variable valve timing system.
  5. Use a high-tech scan tool to test the powertrain control module.
  6. Replace any faulty or damaged components found after diagnosis.

FAQ Section

What repairs can fix the P2647 code?

Repairs that can resolve the issues that are caused by the P2647 trouble code would include:

  •  Adding or changing the engine oil
  • Repairing or replacing wiring or connectors that are associated with the variable valve timing system
  • Replacing the oil control valve or other variable valve timing components
  • Replacing the Rocker Arm Actuator System
  • Replacing the timing belt or chain as well as other timing components
  • Getting rid of any blockage that may be in the valve or oil pressure circuit
  • Replacing the powertrain control module

How serious is the P2647 code?

The P2647 code would be considered serious regardless of the cause but more serious if a timing issue is present. This can cause severe engine damage, especially in interference engines. It is important to have this trouble code diagnosed and repaired as soon as possible.

Can I drive with a P2647 code?

P2647 code is considered serious. It is very important that the vehicle does not get driven much with this trouble code stored as severe engine damage may result. If this issue is not diagnosed sooner rather than later, the repair costs could increase significantly.

How do I know if my rocker arms are bad?

Any kind of fault and damage to the rocker arm will reduce the power of the engine, and even it can cause complete failure of the engine.

Common Symptoms of a bad Rocker Arm are:

  1. Clicking or Ticking Noises
  2. Poor engine performance
  3. Engine stalling  
  4. Illuminated check engine light
  5. Physical deterioration

What does a bad rocker arm sound like?

The most common symptom of a bad rocker arm is clicking or ticking noises coming from the cylinder head of the engine. It can also cause misfires or a stalling engine together with a check engine light on your dashboard.

How do I know if I have a bad lifter?

The most obvious symptom of a faulty hydraulic lifter is the noise it creates in your car’s engine. You can usually distinguish the faulty lifter by the distinct sound. Instead of a knock or ping, a faulty hydraulic lifter will usually make a sound more reminiscent of a tapping sound.

Read More
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