P0116

DTC P0116 Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

DTC Detection Conditions:

A thermistor is built into 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 as 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

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

The 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 output voltage 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).

HINT:
*1: Vehicle is stopped for 20 seconds or more and accelerated to more than 70 km/h (44 mph) within 40 seconds.
*2: Follow these steps: 1) vehicle is driven at 65 km/h (40 mph) or more for 30 seconds or more and the vehicle speed reaches 70 km/h (44 mph); 2) vehicle is decelerated from 65 km/h (40 mph) to 3 km/h (2 mph) or less within 35 seconds; and 3) vehicle is stopped for 10 seconds.

Wiring Diagram:

Step 1-2:

INSPECTION PROCEDURE


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 intelligent 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.