DTC P0116: ECT Sensor Range/Performance Problem

NOTE: If DTC P0117 and/or P0118 are stored at the same time as DTC P0116, troubleshoot those DTCs first, then recheck for DTC P0116.

Start the engine Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, then let it idle.
Check the ECT with the scan tool or the HDS.
Is 176-200°F (80-93°C)or 0.4-0.7 V indicated?
1. YES: Go to step 3.
2. NO: Check the thermostat and the cooling system If they are OK, replace the ECT sensor.
Test drive the vehicle with the scan tool connected, and monitor the thermostat and cooling system for abnormal fluctuations in temperature readings.
Are there any fluctuations in the temperature readings?
1. YES: Check the thermostat and cooling system.
2. NO: Intermittent failure, system is OK at this time.