P0116

DTC P0116 ENGINE COOLANT TEMP. CIRCUIT RANGE/PERFORMANCE PROBLEM

CIRCUIT DESCRIPTION

DTC Detection Condition:

A thermistor is built in the Engine Coolant Temperature (ECT) sensor and changes the resistance value according to the engine coolant temperature.

The structure of the sensor and connection to the ECM is the same the Intake Air Temperature (IAT) sensor.

HINT: If the ECM detects the DTC "P0115, P0117 or P0118", it operates the fail-safe function in which the ECT is assumed to be 80 degrees C (176 degrees F).

MONITOR DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected in the voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.

Examples:

1. Upon starting the engine, the ECT is between 35 degrees C (95 degrees F) and 60 degrees C (140 degrees F). If after driving for 250 seconds, the ECT still remains within 3 degrees C (5.4 degrees F) of the starting temperature, a DTC will be set (2 trip detection logic).
2. Upon starting the engine, the ECT is over 60 degrees C (140 degrees F). If, after driving for 250 seconds, the ECT still remains within 1 degrees C (1.8 degrees F) of the starting temperature, a DTC will be set (6 trip detection logic).

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

Wiring Diagram:

INSPECTION PROCEDURE

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

HINT:
- If DTC P0115, P0116, P0117, P0118 and P0125 are output simultaneously, ECT sensor circuit may be open or shorted. Perform the troubleshooting of DTC P0115, P0117 or P0118 first.

- Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.