Troubleshooting

DTC P0116 Engine Coolant Temp. Circuit Range/Performance Problem

CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the engine coolant temperature.
The lower the engine coolant temperature, the greater the thermistor resistance value, and the higher the engine coolant temperature, the lower the thermistor resistance value.
The engine coolant temperature sensor is connected to the ECM (See the Wiring Diagram below). The 5 volt power source voltage in the ECM is applied to the engine coolant temperature sensor from the terminal THW via a resistor R.
That is, the resistor R and the engine coolant temperature sensor are connected in series. When the resistance value of the engine coolant temperature sensor changes in accordance with changes in the engine coolant temperature, the potential at terminal THW also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.

DETECTING CONDITION





INSPECTION PROCEDURE

HINT: If DTC "P0115" (engine coolant temp. circuit malfunction) and "P0116" (engine coolant temp. circuit range/performance) are output simultaneously, engine coolant temp. sensor circuit may be open.
Perform troubleshooting of DTC P0115 first.

Step 1: