Which Codes Will This Page Cover?
- P2646 “A” Rocker Arm Actuator System Performance/Stuck Off
- P2647 “A” Rocker Arm Actuator System Stuck On
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What Is the P2646 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
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A P2646 code is an OBD code for the Engine Control Module (ECM) detecting that the “A” rocker arm actuator control circuit for bank 1 has a performance issue or is stuck in the off position. Some vehicles, like Hondas, have a variable valve timing and lift electronic control system, often referred to as VTEC, that increases fuel efficiency and engine performance. The VTEC system controls the rocker arm control system through the ECM.
In vehicles equipped with VTEC systems, the rocker arm control solenoid supplies hydraulic pressure to the variable timing and lift mechanism. This allows the VTEC system to adjust valve timing and lift as needed, and the ECM uses the rocker arm oil pressure switch to monitor and verify the oil pressure. This ensures that the variable timing mechanism can properly activate. If the ECM doesn’t receive the proper voltage signal from the rocker arm oil pressure switch, it will set the P2646 code. Furthermore, the “A” in this code refers to the intake camshaft, vehicle the bank 1 refers to the side of the engine that houses the number one cylinder.
What Are the Symptoms of a P2646 Code?
The first symptom that you can expect when confronted with the P2646 code is that the ECM will trigger the Check Engine Light to illuminate on your dashboard. A decrease in engine performance usually accompanies this because the engine valve is not moving or operating as it should. There will also be a very noticeable and loud noise if one or more rockers are stuck in the wrong position. This can also lead to increased fuel consumption and engine performance issues.
What Are Some Causes of a P2646 Code?
One of the most common causes of the P2646 code is when the ECM detects a problem in the rocker arm system for bank 1. Low or dirty engine oil will also cause the code to set and low oil pressure that doesn’t meet the manufacturer’s specifications. Oil pressure sensor failure with the rocker arm is also a potential cause, and faulty rocker arm oil control solenoids will cause the code to set too. Wiring issues can also cause the P2646 code to appear. A qualified technician should inspect any potential wiring issues when diagnosing this issue. Furthermore, if the engine has excessive sludge binding the rockers from moving, or if the oil is too thick, this will also cause the code to show. Also, incorrect oil viscosity will cause the system to cease working as it should.
How Serious Is the P2646 Code?
The P2646 code for the “A” rocker arm control circuit is critical because when the valve timing system is not working correctly, the engine will experience low power and performance. In addition, this error code could cause severe problems for other engine internals and cause fuel consumption to increase. Therefore, address the issue immediately so that you avoid any more severe damage to the engine.
Can I Still Drive with a P2646 Code?
Since the P2646 code can cause the variable valve timing system in your engine to potentially cease working altogether, driving for prolonged periods is not recommended by qualified technicians. You are risking further damage to your engine’s internal components and costlier repairs down the line. In addition, operating your vehicle whenever it’s not running efficiently is always dangerous because you are putting unnecessary stress and strain on your engine. Qualified technicians recommend having your car inspected at a certified service center as soon as possible.
How Easy Is It to Diagnose a P2646 Code?
It’s essential to have your vehicle properly diagnosed by a qualified technician when you have a P2646 issue because misdiagnosis can lead to further engine damage. One of the first steps a technician will take when diagnosing a P2646 code is to verify that the engine maintains the correct oil level and has the proper viscosity. They will then check all electrical connections and sensors tied to the “A” rocker arm actuator system and inspect the wiring for cracks and corrosion. Furthermore, the technician will check that the oil passages are clear and free of any clogs. They will then scan and record any freeze frame data to document the condition of the engine when the P2646 code first appeared.
How Difficult Is It to Inspect a P2646 Code?
Inspecting the P2646 code issue takes several steps and should be left to qualified technicians with previous experience working on these issues. Attempting to DIY this yourself can further damage your engine and its internals. A technician will usually replace the “A” rocker arm actuator and repair the wiring harness or connectors leading to the actuator to inspect and repair the problem. They may also change the oil and filter to correct the oil viscosity and flush the engine passages of sludge if needed.
Need Additional Help with Your P2646 Code?
By following the guidelines we have laid out here, you should spot the signs of a P2646 issue and correct the problem before it worsens. Taking your vehicle to a qualified technician will ensure that your car continues to run healthy and stay on the road longer.
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