DTC Code P0682 – What does this code mean?

<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: The illumination of the engine light indicates a detected fault in the glow plug circuit for cylinder 12. This is a direct result of the DTC code P0682.</li> <li><b>Lack/Loss of Power</b>: A faulty glow plug circuit can lead to incomplete combustion, causing a noticeable reduction in engine power. This is often linked to the P0682 code.</li> <li><b>The engine may be harder to start</b>: Glow plugs are essential for starting diesel engines, especially in cold conditions. A fault in the glow plug circuit for cylinder 12 can make the engine harder to start.</li> <li><b>Engine hesitation</b>: Intermittent or poor performance of the glow plug circuit can cause the engine to hesitate during acceleration, which is a common symptom associated with the P0682 code.</li> </ul>

<ul><li>The cylinder #12 glow plug may be defective, leading to improper heating and starting issues.</li><li>An open or shorted harness in the cylinder #12 glow plug can disrupt the electrical flow, causing the circuit fault.</li><li>Poor electrical connections in the cylinder #12 glow plug circuit can result in intermittent or failed operation.</li><li>A malfunctioning glow plug module can fail to control the glow plug properly, triggering the fault code.</li></ul>

<ul> <li><b>Initial Scan</b>: Use an OBD-II scanner to confirm the presence of DTC P0682 and check for any additional codes.</li> <li><b>Visual Inspection</b>: Inspect the glow plug and its wiring for any visible damage, corrosion, or loose connections.</li> <li><b>Check Glow Plug Resistance</b>: Use a multimeter to measure the resistance of the glow plug. Compare the reading to the manufacturer's specifications.</li> <li><b>Test Glow Plug Relay</b>: Verify the operation of the glow plug relay by checking for continuity and proper function.</li> <li><b>Inspect Control Module</b>: Check the Engine Control Module (ECM) for any signs of damage or malfunction that could affect the glow plug circuit.</li> <li><b>Check Power Supply</b>: Ensure that the glow plug circuit is receiving the correct voltage from the battery and alternator.</li> <li><b>Perform Circuit Continuity Test</b>: Test the continuity of the wiring between the ECM and the glow plug to identify any breaks or shorts.</li> <li><b>Replace Faulty Components</b>: Replace any damaged or faulty components identified during the diagnostic process, such as the glow plug, relay, or wiring.</li> <li><b>Clear Codes and Test Drive</b>: Clear the DTC codes using the OBD-II scanner and perform a test drive to ensure the issue is resolved.</li></ul>

<p>The DTC code P0682 indicates a Cylinder 12 Glow Plug Circuit Fault. This is a critical issue, especially in diesel engines, as it affects the engine's ability to start and run efficiently.</p><ul><li><b>Immediate Actions:</b> Inspect and replace the faulty glow plug and check the associated wiring and connectors.</li><li><b>Potential Risks:</b> Delayed repair can lead to hard starting, increased emissions, and potential engine damage.</li></ul>