<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: <b>Engine Light ON</b> indicates a problem with the vehicle's communication network. <b>Potential causes</b> include a faulty control module, wiring issues, or a malfunctioning sensor.</li> <li><b>Communication Errors</b>: <b>Communication Errors</b> between control modules can lead to erratic vehicle behavior. <b>Potential causes</b> include damaged wiring, poor connections, or a defective control module.</li> <li><b>Vehicle Performance Issues</b>: <b>Vehicle Performance Issues</b> such as stalling, poor acceleration, or irregular idling may occur. <b>Potential causes</b> include incorrect data being sent or received by the control modules.</li> </ul>

<ul><li>The module responsible for communication is faulty and not transmitting data correctly.</li><li>The wiring harness connected to the module is either open or has a short circuit, disrupting data flow.</li><li>There is a poor electrical connection in the module circuit, leading to intermittent or failed communication.</li></ul>

<ul> <li><b>Initial Scan</b>: Perform a comprehensive scan of the vehicle's control modules to confirm the presence of DTC U1224 and check for any additional related codes.</li> <li><b>Inspect Wiring and Connectors</b>: Visually inspect the wiring and connectors associated with the communication network for any signs of damage, corrosion, or loose connections.</li> <li><b>Check Network Integrity</b>: Use a multimeter to measure the resistance and continuity of the communication lines. Ensure the network integrity is within the manufacturer's specifications.</li> <li><b>Verify Power and Ground</b>: Ensure that all control modules on the network have proper power and ground connections. Check for blown fuses or faulty relays.</li> <li><b>Module Communication Test</b>: Use a diagnostic tool to perform a communication test between the control modules. Identify any module that fails to communicate properly.</li> <li><b>Update or Reprogram Modules</b>: Check for any available software updates or reprogramming procedures for the control modules. Perform updates as necessary.</li> <li><b>Clear Codes and Test Drive</b>: Clear the DTC codes and perform a test drive to ensure the issue has been resolved. Monitor the vehicle's communication network for any reoccurrence of the code.</li></ul>

<p>The DTC code U1224 indicates 'Invalid Or Missing Data For Primary Id'. This is a critical issue as it affects the communication between essential control modules.</p><ul><li><b>Immediate Actions:</b> Inspect and repair the communication network wiring and connectors.</li><li><b>Potential Risks:</b> Delayed repair can lead to malfunctioning of critical systems, potentially causing unsafe driving conditions.</li></ul>