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P3446 Cylinder 6 Exhaust Valve Control Circuit Performance GuideMechanic.Com Modern internal combustion engines are increasingly engineered to be more fuel-efficient and environmentally friendly. One of the technologies aiding this mission is cylinder deactivation, which allows the engine to deactivate specific cylinders under light load conditions to improve fuel economy. This system depends heavily on precise valve control, particularly through solenoids that manage intake and exhaust valve lifters.
When a diagnostic trouble code like P3446 appears, it indicates the control system for the exhaust valve in cylinder 6 is not performing as expected. While not necessarily catastrophic, this issue can lead to reduced fuel efficiency, increased emissions, and long-term engine wear if left unaddressed.
In this article, we will explore the details of code P3446, including its meaning, causes, symptoms, diagnostic procedures, and potential fixes.
See Also: P3445 Cylinder 6 Exhaust Valve Control Circuit/Open
P3446 Cylinder 6 Exhaust Valve Control Circuit Performance
What Does Code P3446 Mean?
DTC Definition: P3446 – Cylinder 6 Exhaust Valve Control Circuit Performance
This trouble code refers to an abnormal performance issue within the electrical circuit that controls the exhaust valve for cylinder 6.
Unlike codes that indicate an open or short circuit, a “performance” code suggests that the circuit is operating but not within the expected parameters.
This could mean slower than expected activation, incorrect voltage patterns, or inconsistent signals from the solenoid or related components.
This malfunction can interfere with the cylinder deactivation system (also called Active Fuel Management or Displacement on Demand), leading to improper deactivation of cylinder 6.
Understanding Cylinder Deactivation
Cylinder deactivation systems are designed to reduce fuel consumption by temporarily shutting down some cylinders during light engine loads, such as highway cruising. In V6 and V8 engines, this is commonly achieved through:
Oil control solenoids that direct oil pressure to special hydraulic lifters.
These lifters then collapse to prevent the exhaust and intake valves from opening.
This deactivates the cylinder, reducing fuel use and emissions.
The system reactivates the cylinder when engine load increases.
If the exhaust valve control solenoid for cylinder 6 is underperforming, the cylinder may not deactivate properly, triggering P3446.
P3446 Cylinder 6 Exhaust Valve Control Circuit Performance
Symptoms of Code P3446
The symptoms associated with P3446 can vary based on the severity and duration of the malfunction. Common signs include:
Illuminated Check Engine Light (CEL)
Reduced fuel economy
Rough idling
Engine hesitation during acceleration
Intermittent misfires
Poor overall engine performance
Increased tailpipe emissions
In some cases, the driver may not notice any major drivability concerns, especially in the early stages. However, over time, performance may degrade.
What Causes P3446?
Several issues can cause the performance of the exhaust valve control circuit for cylinder 6 to degrade. Common culprits include:
1. Faulty Exhaust Valve Control Solenoid
The solenoid may be clogged, weak, or suffering from internal electrical issues, resulting in slow or inconsistent activation.
2. Wiring or Connector Problems
Loose, frayed, corroded, or damaged wiring can introduce electrical resistance or cause intermittent signal loss, affecting solenoid performance.
3. Valve Lifter Oil Manifold (VLOM) Failure
The VLOM assembly distributes oil pressure to the lifters. A malfunctioning VLOM may supply incorrect pressure or misfire a signal.
4. Low or Contaminated Engine Oil
Poor oil quality or low oil levels can reduce hydraulic pressure or clog oil passages, preventing the solenoid from performing correctly.
5. Internal Engine Sludge
Sludge buildup in the oil system can impair valve actuation or clog small oil passages within the solenoids or VLOM.
6. Faulty ECM (Engine Control Module)
Though rare, a misbehaving ECM may not accurately control or interpret signals in the valve control circuit.
P3446 Cylinder 6 Exhaust Valve Control Circuit Performance
Diagnosing P3446
To properly diagnose P3446, a step-by-step process using specialized diagnostic equipment is required. Here’s how technicians generally approach it:
1. Scan for Additional Trouble Codes
Use an OBD-II scanner to read all present and pending codes. Other related codes (such as P3445, P3447, etc.) may point to a broader system issue.
2. Review Freeze Frame Data
Freeze frame data reveals the engine’s condition at the moment the code was stored. Look at RPM, load, oil pressure, and temperature.
3. Perform a Visual Inspection
Inspect the wiring harness and connectors going to the exhaust valve control solenoid on cylinder 6. Look for wear, corrosion, or disconnections.
4. Test the Solenoid
Use a multimeter to measure resistance across the solenoid terminals. Normal resistance is typically between 6–10 ohms. Irregular resistance could indicate a solenoid problem.
5. Check Oil Level and Condition
Ensure the engine has the correct type and amount of oil. Examine the oil for signs of contamination or sludge.
6. Perform Continuity Tests
Check for continuity between the ECM and the solenoid. Resistance in the wiring should be minimal.
7. Command Solenoid Activation
Using a scan tool, command the solenoid to activate and listen for operation. A sluggish or silent solenoid may indicate internal failure or clogging.
P3446 Cylinder 6 Exhaust Valve Control Circuit Performance
How to Fix P3446
After identifying the root cause, the following repairs may resolve P3446:
1. Replace the Exhaust Valve Control Solenoid (Cylinder 6)
If the solenoid is slow, sticky, or electrically weak, replacing it often solves the issue.
2. Repair or Replace Wiring and Connectors
Fix damaged wires, remove corrosion from terminals, and ensure all connections are tight and secure.
3. Replace or Clean the VLOM Assembly
If the Valve Lifter Oil Manifold is obstructed or malfunctioning, cleaning or replacing it may be required.
4. Change Engine Oil and Filter
Flush out old or dirty oil and use the manufacturer-recommended oil type and viscosity.
5. ECM Reflash or Replacement
In rare cases, if the ECM is not sending accurate signals or has software bugs, reprogramming or replacing it may be necessary.
P3446 Cylinder 6 Exhaust Valve Control Circuit Performance
Can You Drive with P3446?
Driving with a P3446 code may be possible, but it is not recommended for extended periods. Risks of ignoring the issue include:
Reduced fuel economy
Rough engine operation
Higher emissions
Potential engine damage if misfires occur
Catalytic converter damage from incomplete combustion
Addressing the problem early will save fuel, protect your engine, and help your vehicle pass emissions inspections.
Preventing P3446
Preventive maintenance and regular inspections are key to avoiding this type of trouble code in the future:
Use High-Quality Oil – Always use the manufacturer-recommended oil type and change it at scheduled intervals.
Avoid Prolonged Engine Idling – This can lead to oil contamination and sludge buildup.
Inspect Wiring During Tune-Ups – A quick check of wiring and connectors can reveal potential issues early.
Avoid Engine Overheating – Heat accelerates oil degradation and can damage sensitive solenoid components.
Respond Promptly to Warning Lights – Delaying diagnostics can lead to more expensive repairs.
Conclusion
P3446 is a performance fault in the exhaust valve control circuit for cylinder 6, often stemming from solenoid malfunctions, wiring problems, or oil-related issues. While not immediately disabling, this code indicates that your engine’s fuel-saving features are not working as designed.
Diagnosing the issue thoroughly and repairing it promptly will restore performance, fuel economy, and long-term reliability.
With the right approach, including regular maintenance and oil changes, you can minimize the risk of encountering this issue in the future.
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