<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: <b>Engine Light ON</b> indicates a detected issue with the cruise control module software. <ul><li>Potential causes: Software incompatibility, faulty cruise control module, or incorrect software update.</li></ul></li> <li><b>Cruise Control Malfunction</b>: <b>Cruise Control Malfunction</b> may occur, leading to the inability to set or maintain a constant speed. <ul><li>Potential causes: Software incompatibility, communication errors between modules, or a defective cruise control module.</li></ul></li> <li><b>Erratic Vehicle Speed</b>: <b>Erratic Vehicle Speed</b> can be experienced due to improper functioning of the cruise control system. <ul><li>Potential causes: Software issues, faulty cruise control module, or disrupted communication with the engine control unit (ECU).</li></ul></li> </ul>

<ul><li>The cruise control module may have been programmed with incorrect software, leading to communication issues with other vehicle systems.</li><li>A faulty cruise control module can cause software incompatibility, resulting in the inability to properly control the cruise functions.</li></ul>

<ul> <li><b>Initial Scan</b>: Perform a comprehensive scan of the vehicle's control modules using an OBD-II scanner to confirm the presence of DTC U0305.</li> <li><b>Check Software Version</b>: Verify the software version of the Cruise Control Module (CCM) and compare it with the latest version available from the manufacturer.</li> <li><b>Inspect Wiring and Connections</b>: Inspect the wiring harness and connectors related to the CCM for any signs of damage, corrosion, or loose connections.</li> <li><b>Update Software</b>: If the software version is outdated, perform a software update on the CCM using the manufacturer's recommended procedure and tools.</li> <li><b>Clear DTCs and Test Drive</b>: Clear the DTCs from the vehicle's memory and conduct a test drive to ensure the issue is resolved and the DTC U0305 does not reappear.</li> <li><b>Re-scan for DTCs</b>: After the test drive, re-scan the vehicle to confirm that no new DTCs have been set and that U0305 is no longer present.</li></ul>

<p>The DTC code U0305 indicates a <b>software incompatibility with the cruise control module</b>. This is a critical issue as it can affect the vehicle's ability to maintain a set speed, potentially leading to unsafe driving conditions.</p><ul><li>Immediate action: Reprogram or update the cruise control module software.</li><li>Potential risks: Loss of cruise control functionality, unexpected acceleration or deceleration.</li></ul>