Test No. 5: Engine Coolant Temperature Gauge Does Not Operate Or Abnormal Operation

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition off. Disconnect single-pin Gray electrical harness connector from engine coolant temperature sending unit. See Figure. Turn ignition on. If engine coolant temperature gauge indicates COOL, go to next step. If engine coolant temperature gauge does not indicate COOL, check wiring harness for short. See INSTRUMENT CLUSTER in SYSTEM WIRING DIAGRAMS article. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .
Turn ignition off. Using jumper wires, connect a 12-volt, 3.4-watt light bulb between engine coolant temperature sending unit single-pin Gray electrical harness connector terminal and good vehicle ground point. With ignition on, test light should be on and engine coolant temperature gauge needle should move toward HOT. If test light is off and gauge needle does not move, check wiring harness for open circuit. Repair as necessary. See INSTRUMENT CLUSTER in SYSTEM WIRING DIAGRAMS article. After repairs have been made, perform confirmation test. See CONFIRMATION TEST . If wire harness is okay, go to next step.

Turn ignition off. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Disconnect 22-pin electrical harness connector C9 and 18-pin electrical harness connector C10 from back side of instrument cluster. See Figure. Measure resistance across specified terminals of engine coolant temperature gauge. See Figure. See ENGINE COOLANT TEMPERATURE GAUGE RESISTANCE table. If resistance is within specification, go to next step. If resistance is not within specification, replace instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .

ENGINE COOLANT TEMPERATURE GAUGE RESISTANCE

Test Between Terminals	Specification (Ohms)
"A" & "B"	250
"C" & "D"	250

Test engine coolant temperature sending unit. See ENGINE COOLANT TEMPERATURE SENDING UNIT under COMPONENT TESTS. If engine coolant temperature sending unit is okay, go to next step. If engine coolant temperature sending unit is not okay, replace engine coolant temperature sending unit. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .
Check ECU-ACC (5-amp), ECU-B (7.5-amp), ECU-IG No. 2 (10-amp), GAUGE No. 1 (10-amp), PANEL (5-amp), and RADIO (15-amp) fuses in driver side junction block located under left side of instrument panel. See Figure. If fuses are okay, go to next step. If fuses are defective, repair short in wiring connected to identified fuse. See INSTRUMENT CLUSTER in SYSTEM WIRING DIAGRAMS article. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .
Check multi-display information center and instrument cluster ground circuits. See INSTRUMENT CLUSTER in SYSTEM WIRING DIAGRAMS article. If ground circuits are faulty, repair and retest system. If ground circuits are okay, substitute original multi-display information center or instrument cluster with a known-good unit and recheck system operation. If system operates properly, original multi-display information center or instrument cluster was defective. If system still does not operate properly, perform multi-display information center, instrument cluster and instrument cluster/multi-display information center electrical harness pin voltage checks. See MULTI-DISPLAY INFORMATION CENTER , INSTRUMENT CLUSTER and INSTRUMENT CLUSTER/MULTI-DISPLAY INFORMATION CENTER ELECTRICAL HARNESS under PIN VOLTAGE TESTS. Check wiring harnesses and electrical connectors for an intermittent problem. Repair wiring harnesses or connectors as necessary. If voltage values, harnesses and connectors are okay, replace multi-display information center and/or instrument cluster. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .