Test E: Incorrect Temperature Gauge Indication (DTC U1073)

Using New Generation Star (NGS) tester, perform instrument cluster self-test. If no DTCs were retrieved, go to next step. If DTC U1073 was retrieved, repair engine performance concern. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. For all other instrument cluster DTC, perform appropriate test in accordance with DTC retrieved. See INSTRUMENT CLUSTER DIAGNOSTIC TROUBLE CODE INDEX table under SELF-DIAGNOSTIC SYSTEM.
Turn ignition switch to RUN position. Using NGS tester, select instrument cluster ENGINE COOLANT CONTROL active command. Trigger ENGCOOLANT active. Monitor engine coolant temperature gauge while adjusting ENGCOOLANT active command to read 50% and 100%. Engine coolant temperature gauge needle should start at cold, move to half (50%), and move to full hot (100%). If engine coolant temperature gauge needle is as specified, check and repair engine coolant temperature concern. If engine coolant temperature gauge needle is not as specified, go to next step.
Disconnect all instrument cluster harness connectors. Inspect for corrosion and pushed out pins. Connect all instrument cluster harness connectors, ensuring they seat correctly. Operate system and verify if concern is still present. If concern is still present, replace instrument cluster. Clear DTCs and perform instrument cluster self-test. If concern is not present, system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.