DTC Code P069D – What does this code mean?

<ul> <li><b>Engine Light ON</b>: <p>The engine light illuminates on the dashboard, indicating a potential issue with the vehicle's systems. This is often the first sign of a problem and should not be ignored.</p> <ul><li><b>Potential Causes:</b> Faulty glow plug, damaged wiring, or a malfunctioning glow plug control module.</li></ul></li> <li><b>Service Engine Soon Warning Light</b>: <p>The 'Service Engine Soon' warning light may also appear, suggesting that the vehicle requires immediate attention to prevent further damage.</p> <ul><li><b>Potential Causes:</b> Issues with the glow plug control circuit, such as high resistance or an open circuit.</li></ul></li> </ul>

<ul><li>Faulty cylinder #10 glow plug can cause the control circuit to register high voltage.</li><li>An open or shorted harness in cylinder #10 glow plug can disrupt the circuit's normal operation.</li><li>Poor electrical connection in the cylinder #10 glow plug circuit can lead to high resistance and incorrect readings.</li><li>A faulty glow plug module can fail to regulate the voltage properly, causing the control circuit to show high.</li></ul>

<ul> <li><b>Initial Preparation</b>: Gather a diagnostic scanner, vehicle information source, and a digital volt/ohmmeter (DVOM). Search for applicable technical service bulletins (TSB) related to the vehicle make, model, and symptoms.</li> <li><b>Visual Inspection</b>: Perform a careful visual inspection of all glow plug and glow plug control wiring and connectors for any signs of damage or corrosion.</li> <li><b>Retrieve Codes and Data</b>: Connect the diagnostic scanner to the vehicle diagnostic port. Retrieve all stored codes and freeze frame data, and record it for later reference.</li> <li><b>Test Drive</b>: Test drive the vehicle to see if the code P069D is reset. Drive until the PCM enters readiness mode or the code is reset. If the code is not reset, it may be an intermittent issue.</li> <li><b>Glow Plug Testing</b>: Remove the glow plugs and apply battery voltage to test them. If the glow plug glows bright red, it is good. If it fails to heat up, it likely does not meet manufacturer’s specifications for resistance.</li> <li><b>Activate Glow Plug Timer</b>: Use the scanner to activate the glow plug timer and test for battery voltage and ground at the glow plug connector using the DVOM.</li> <li><b>Power Supply Testing</b>: If no voltage is present, test the power supply for the glow plug timer or glow plug controller. Test all related fuses and relays as recommended by the manufacturer.</li> <li><b>Output Voltage Testing</b>: Use the DVOM to test output voltage at the glow plug timer or PCM. If voltage is detected, suspect an open or shorted circuit. Seek out the cause or replace the circuit.</li> <li><b>Verify Correct Cylinder</b>: Ensure you are diagnosing the correct cylinder to avoid unnecessary troubleshooting. Confirm the cylinder number before proceeding.</li></ul>

<p>The DTC code P069D indicates a high voltage issue in the Cylinder 10 Glow Plug Control Circuit. This is a <b>critical</b> issue as it can lead to starting problems, increased emissions, and potential engine damage. Immediate actions should include inspecting the glow plug, control module, and associated wiring for faults. Delayed repair can result in severe engine performance issues and higher repair costs.</p>