P2646 Honda Trouble Code | Rocker Arm actuator [stuck off]

Are you getting a P2646 trouble code?

So if you are getting P2646 trouble code on your vehicle’s OBD(On-Board Diagnostics) system while facing a problem in your vehicle, and you don’t know what it means, then don’t worry we are here to give you every possible knowledge about this error code.

[For Beginner] What is the OBD system?

On-Board Diagnostics is a built-in system in your vehicle for diagnosing problems, it sets error codes which in turn tells you about which part of your vehicle is not working properly.

There are different codes for different troubles.

What does P2646 Honda trouble code indicate?

P2646 is a diagnostic trouble code that applies to vehicles with OBD2 systems.

The definition of this code is ” ‘A’ Rocker Arm Actuator System Performance/ Stuck off Bank 1″.

So as you can see, it is very difficult to understand anything about this code with just this definition so in case you are getting this trouble code this article will be very informative to you.

The P2646 code indicates the problem with the rocker arm actuator which means either the actuator is not working properly or it is stuck in the off position.

Bank 1 in the definition indicates the engine side where the cylinder 1 is present and the letter ‘A’ indicates the Intake camshaft.

So getting the P2646 trouble code means that the electronic control module of your vehicle has detected some problem in getting feedback from the rocker arm actuator.

What is the rocker arm actuator system?

Before going in deep we first need to know about what the rocker arm actuator does in the vehicle.

The electronic control module regulates various actuators on the internal combustion engine and one of the actuators that ECM regulates is the rocker arm actuator.

A rocket arm actuator system is a switch that controls the flow and pressure of oil in the engine and it also consists of oil passages.

What causes the P2646 trouble code?

The factors that can cause this error code to occur are:-

• Maybe there is excessive sludge that is clogging the actuator.
• The pressure of the oil in the engine is not up to the specifications.
• Oil passages are clogging.
• Fault in the electronic control module.
• Inappropriate level of oil. 
• You are using incorrect oil.
• Poor electrical connection.

How to know that your vehicle is having this trouble code?

There are some symptoms of this trouble code which will tell you that your vehicle is having this trouble, these symptoms are

• Your vehicle will use more fuel which means it will become less fuel-efficient.
• The engine valve train of your vehicle will produce noise if the actuator is stuck in an off position.
• The maximum speed of your vehicle will reduce to less than 40 miles per hour.
• The engine light will start illuminating.
• The performance of your vehicle’s engine will reduce.
• The valve of the engine will stop moving in the direction in which it should move.
• Your vehicle will face problems in accelerating.

Fixing P2646 Code:

Try out these following fixes to fix the P2646 code

Replace ‘A’ Rocker Arm Actuator:

Replacing ‘A’ rocker arm actuator can solve your problem, but this is not always the case as sometimes there is no need to replace the actuator because the fault can be in the oil also like.

• The oil pressure can be inadequate.
• The level of the oil is low.
• The viscosity of the oil is not as per requirement.

But sometimes mechanics or people itself replace the rocker arm actuator without checking these things and this costs them even more, so you should always keep in mind to check these things first before replacing the rocker arm actuator to save your money from wasting.

Check the level of the oil:

If the pressure of the oil in your engine is low then it must be because of the low level of the oil, so properly check the level of oil and if it is low then fill it up to the mark, maybe doing this will solve your problem, but if the problem persists then also try the other fixes.

Check viscosity:

After checking the level of the oil if you realize that level is correct then check the viscosity of the oil as it is also an important factor for the proper functioning of the actuator, if the viscosity of the oil is low then it will not build the proper pressure required.

Change the oil with the oil having proper viscosity.

Check for the sludge:

If the viscosity and level of the oil are correct then there are chances of having excessive sludge in the oil passage, sludge can clog the oil passage and stop the operation of VTEC, so to remove the sludge perform engine oil flush.

Repair the electrical connections:

Check for any damage in the connectors and wiring of the electrical connections and repair if any fault is present.

Points to note down:

Please remember these things while fixing the trouble 

1. Do not replace the actuator without checking the other things, as problems can be in other things also.
2. Determine the viscosity of the oil correctly as many times the wrong determination of viscosity can cover the fault.
3. Clear the error codes after resolving the trouble.

Frequently Asked Questions

Q1: How to correctly diagnose a trouble code?

Many times it will happen that maybe you can not determine the trouble code by looking at the symptoms of the codes.

So if you see your engine light is on then it is indicating that the diagnostic system of your vehicle has detected some problem in the vehicle. The diagnostic system will also set some codes which will correspond to the problem that your vehicle has.

So to read those codes set by the diagnostic system of the vehicle do the following

1. Plug the code reader or scanning tool into the 16-pin OBD II diagnostic connector of your vehicle.
2. Now turn on the ignition of the engine to enable communication between the scan tool and the car’s computer.
3. Press the read code button present on the tool menu of the code reader or scanner.
4. The scan tool will display all the trouble codes.
5. To erase the codes press the clear codes option on the tool menu.

Q2: What are the symptoms of a bad oil pressure sensor?

Oil pressure sensor regulates the pressure of the oil in the vehicle, however, when this sensor does not work properly you will determine it by

1. When the low oil light on the dashboard will blink you will think that your oil level is low but on checking if the level is not low then there might be a defect in your oil pressure sensor.
2. If your vehicle has a mechanical gauge and it is showing oil level to zero, but when you check the level is not zero then your sensor is faulty.
3. If your vehicle has an electronic gauge then a faulty sensor will show weird readings or will show zero or full.
4. If the low oil pressure warning light turns on even after having the correct level of oil.

Q3: How much will it cost to diagnose P2646?

Diagnosing P2646 trouble will take 1 hour of labor, most of the auto repair shops charge $75-$150 for 1 hour, it may vary from shop to shop.