<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: The illumination of the engine light indicates a detected issue with the exhaust valve control circuit for cylinder 12. This could be due to a malfunction in the control circuit, a faulty exhaust valve actuator, or wiring issues.</li> <li><b>Reduced Engine Performance</b>: A malfunction in the exhaust valve control circuit can lead to suboptimal engine performance, including reduced power and efficiency. This is often caused by improper valve timing or a failure in the actuator.</li> <li><b>Rough Idling</b>: The engine may experience rough idling due to improper exhaust valve operation. This can be linked to issues in the control circuit or a defective valve actuator.</li> <li><b>Increased Emissions</b>: Faulty exhaust valve control can lead to incomplete combustion, resulting in higher emissions. This is typically due to the exhaust valve not opening or closing at the correct times.</li> </ul>

<ul><li>Low oil pressure can prevent the proper operation of the exhaust valve control circuit.</li><li>Restricted oil passage may impede the flow of oil, affecting the cylinder deactivation system.</li><li>Engine mechanical condition issues can lead to improper functioning of the exhaust valve control circuit.</li><li>A faulty Cylinder Deactivation Solenoid can cause the circuit to operate incorrectly.</li><li>An open or shorted Cylinder Deactivation Solenoid harness can disrupt the electrical connection needed for proper operation.</li><li>Poor electrical connection in the Cylinder Deactivation Solenoid circuit can lead to intermittent or failed operation.</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 12 Exhaust Valve Control Circuit Components</b>: Identify all components associated with the cylinder 12 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 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 12 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 P3495 indicates a <b>Cylinder 12 Exhaust Valve Control Circuit Low</b> issue. This is a critical problem as it affects the engine's performance and can lead to severe engine damage if not addressed immediately.</p><ul><li>Potential risks include misfires, reduced power, and increased emissions.</li><li>Immediate actions should involve inspecting the wiring, connectors, and the exhaust valve control solenoid for faults.</li></ul>