Skip the auto shop - Our mechanics make house calls

P2646 OBD-II Trouble Code: 'A' Rocker Arm Actuator System Performance / Stuck Off Bank 1

Check Engine Light

P2646 code definition

'A' Rocker Arm Actuator System Performance or Stuck Off Bank 1

What the P2646 code means

P2646 is an OBD-II generic code for the engine control module (ECM) detecting the 'A' rocker arm actuator control circuit for bank 1 has a performance problem or is stuck in the off position.

What causes the P2646 code?

  • The ECM detects a problem in the rocker arm system for bank 1.
  • The oil passages are clogged or the oil pressure is not up to specifications.
  • The rocker arm actuator is clogged with sludge or is sticking intermittently.
  • The engine may have excessive sludge binding the rockers from moving or the oil is too thick.
  • The incorrect oil viscosity is being used. Too thick of an oil will cause the system to not work as designed.

What are the symptoms of the P2646 code?

  • The engine valve train will not move as designed causing a low power condition.
  • The Check Engine Light will be illuminated.
  • The valve train may be excessively noisy if one or more rockers are stuck in the incorrect position.

How does a mechanic diagnose the P2646 code?

  • Scans codes and documents the code in the ECM and views the freeze frame data for the code
  • Verifies the oil is full of the correct viscosity oil
  • Performs the manufacturer pinpoint test on the 'A' rocker arm actuator system since testing may be different between applications and manufacturers

Common mistakes when diagnosing the P2646 code?

  • Replacing the actuator without verifying the actuator is the cause of the problem
  • Failing to clear the ECM codes after the system is repaired
  • Failing to identify that incorrect oil viscosity is being used causing the code

How serious is the P2646 code?

Code P2646 is a code for the 'A' rocker arm control circuit performance problem. When the system is not working correctly, the rocker arms are not moving to the different position causing a low power situation.

What repairs can fix the P2646 code?

  • Replacing the 'A' rocker arm actuator
  • Repairing the wiring harness or connector to the actuator
  • Changing the oil and filter to the correct viscosity oil
  • Flush the engine passages of sludge from lack of oil changes

Additional comments for consideration regarding the P2646 code

Code P2646 is not a very common code since most vehicles do not have actuators for the rocker arms of the engines they manufacture. The vehicles that have variable rockers that use this code are known to get this code when the engine gets sludged up from lack of oil changes at the proper interval, or if the oil is too thick of a viscosity and does not flow properly through the small passages as required. Normal oil change intervals with the correct oil viscosity will usually fix most of these codes if the engine is not too sludged up.

Need help with a P2646 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
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
P0291OBD-II Trouble Code: Cylinder 11 Injector Circuit Low
P0291 code definition When your vehicle’s PCM registers the P0291 code, it means that a voltage reading came from the fuel injector circuit – for cylinder number 11’s fuel injector –...


Related questions

Q: Car revs high

Air leaks into the intake system (a loose hose, or the EVAP valve as you have already experienced). If there are no codes, even transient codes which may not set the Check Engine Light, the problem could be a loose...

Q: My cars enginefail safe mode has activated and I am curios what I would need to check to fix this.

Your engine fail safe is a protection mode so additional damage and safety is important. I would recommend having the computer scanned to see if the computer systems have set a code that needs repaired. The vehicle could go into...

Q: AC failed and started running rough and the Check Engine Light came on. But NOW its fine.

I wouldn't concern yourself with the timing of your cars symptoms. When a car fails, I liken it to when a light bulb decides to burn out. It was just its time. Everything will eventually fail. I also would strongly...