<ul> <li><b>Engine Light ON</b>: The Engine Light or Service Engine Soon Warning Light illuminates, indicating an issue with the exhaust valve control circuit for cylinder 3. This can be caused by a faulty exhaust valve control solenoid, wiring issues, or a malfunctioning Engine Control Module (ECM).</li> <li><b>Reduced Engine Performance</b>: The vehicle may experience reduced engine performance due to improper exhaust valve operation. This can lead to decreased power and acceleration, often caused by a malfunctioning exhaust valve control solenoid or wiring issues.</li> <li><b>Rough Idling</b>: The engine may idle roughly or inconsistently, which can be attributed to the exhaust valve for cylinder 3 not operating correctly. Potential causes include a defective exhaust valve control solenoid or issues with the control circuit wiring.</li> <li><b>Increased Emissions</b>: Higher emissions may be observed due to improper exhaust valve timing, which can affect the combustion process. This symptom is often linked to a faulty exhaust valve control solenoid or ECM issues.</li> </ul>

<ul><li>Low oil pressure can prevent the proper operation of the cylinder deactivation system.</li><li>Restricted oil passage may impede the flow of oil to the deactivation solenoid.</li><li>Engine mechanical condition issues can affect the performance of the exhaust valve control circuit.</li><li>A faulty cylinder deactivation solenoid can cause the circuit to read low.</li><li>An open or shorted cylinder deactivation solenoid harness can disrupt the electrical signal.</li><li>Poor electrical connection in the cylinder deactivation solenoid circuit can lead to intermittent or low voltage readings.</li></ul>

<ul> <li><b>Research Technical Service Bulletins (TSBs)</b>: Research TSBs for the specific vehicle by year, model, and engine to identify any known fixes for this issue.</li> <li><b>Check Engine Oil Condition</b>: Confirm the engine oil is at the appropriate level and in good condition. Low or dirty oil can affect the variable valve timing system.</li> <li><b>Locate Cylinder 3 Exhaust Valve Control Components</b>: Identify and locate all components associated with the cylinder 3 exhaust valve control circuit, including the variable valve timing solenoid, switches, fault indicators, and the ECM.</li> <li><b>Perform Visual Inspection</b>: Inspect the associated wiring for defects such as scraping, rubbing, bare wires, or burn spots. Check connectors and connections for security, corrosion, and damaged pins.</li> <li><b>Test Variable Valve Timing Solenoid</b>: Test the variable valve timing solenoid for proper operation. Replace if faulty.</li> <li><b>Check for Blocked Oil Passages</b>: Inspect and clear any blocked oil passages that could affect the variable valve timing system.</li> <li><b>Inspect and Repair Wiring</b>: Repair or replace any faulty wiring in the cylinder 3 exhaust valve control circuit.</li> <li><b>Flash or Replace ECM</b>: If all other components are functioning correctly, consider flashing or replacing the ECM.</li> <li><b>Clear DTC and Test Drive</b>: Clear the DTC code and perform a test drive to ensure the issue is resolved.</li></ul>

<p>The DTC code P3423 indicates a <b>Cylinder 3 Exhaust Valve Control Circuit Low</b> issue. This is a critical problem as it affects engine performance and emissions.</p><ul><li>Immediate action is required to prevent potential engine damage.</li><li>Inspect the exhaust valve control circuit for faults.</li><li>Check wiring, connectors, and the control module.</li><li>Failure to address this promptly can lead to severe engine damage and increased emissions.</li></ul>