<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: <b>Engine Light ON</b> indicates a problem with the evaporative emission system. This can be caused by a high voltage in the leak detection pump sense circuit. Potential causes include a faulty leak detection pump, damaged wiring, or a malfunctioning control module.</li> <li><b>Failed Emissions Test</b>: <b>Failed Emissions Test</b> can occur due to the evaporative emission system not functioning correctly. This is often linked to issues in the leak detection pump sense circuit, which may be caused by electrical faults or component failures.</li> <li><b>Fuel Odor</b>: <b>Fuel Odor</b> may be noticeable if there is a leak in the evaporative emission system. This symptom can be associated with a high voltage in the leak detection pump sense circuit, potentially due to a defective pump or wiring issues.</li> </ul>

<ul><li>The EVAP System Leak Detection Pump may be faulty, leading to incorrect readings and triggering the error code.</li><li>An open or shorted harness in the EVAP System Leak Detection Pump can disrupt the signal, causing the system to detect a high circuit condition.</li><li>Poor electrical connections in the EVAP System Leak Detection Pump circuit can result in intermittent or failed communication, leading to the error code.</li></ul>

<ul> <li><b>Initial Scan</b>: Use an OBD-II scanner to confirm the presence of DTC P2406 and check for any additional codes that may be related.</li> <li><b>Visual Inspection</b>: Inspect the EVAP system components, including hoses, connectors, and the leak detection pump for any visible damage or disconnections.</li> <li><b>Check Electrical Connections</b>: Verify that all electrical connections to the leak detection pump are secure and free of corrosion or damage.</li> <li><b>Test Leak Detection Pump</b>: Using a multimeter, measure the voltage at the leak detection pump. Compare the readings to the manufacturer's specifications to ensure proper operation.</li> <li><b>Inspect Wiring Harness</b>: Check the wiring harness for any signs of wear, fraying, or damage that could cause a high circuit condition.</li> <li><b>Check Ground Connections</b>: Ensure that the ground connections for the EVAP system are clean, tight, and free of corrosion.</li> <li><b>Perform Smoke Test</b>: Conduct a smoke test to identify any leaks in the EVAP system that could be causing the issue.</li> <li><b>Replace Faulty Components</b>: If any components are found to be faulty during testing, replace them and clear the DTC code. Re-scan to confirm the issue is resolved.</li></ul>

<p>The DTC code P2406 indicates a high voltage issue in the Evaporative Emission System Leak Detection Pump Sense Circuit. This is a critical issue as it can lead to increased emissions and potential fuel system damage.</p><ul><li><b>Immediate Actions:</b> Inspect the leak detection pump and associated wiring for faults.</li><li>Check for any loose or corroded connections.</li><li>Replace any damaged components immediately.</li></ul><p>Delaying repair can result in failed emissions tests and further damage to the evaporative emission system.</p>