DTC    P0116    Engine Coolant Temperature Circuit Range / Performance Problem

for Preparation Click here


DESCRIPTION

Refer to DTC P0115 on page Click here.

DTC No.
DTC Detection Condition
Trouble Area
P0116
Case 1:
Engine Coolant Temperature (ECT) between 35°C and 60°C (95°F and 140°F) when engine started, and conditions (a) and (b) met (2 trip detection logic):
(a) Vehicle driven at varying speeds (accelerated and decelerated)
(b) ECT remains within 3°C (5.4°F) of initial ECT
Case 2:
ECT more than 60°C (140°F) when engine started, and conditions (a) and (b) met (6 trip detection logic):
(a) Vehicle driven at varying speeds (accelerated and decelerated)
(b) ECT measurements remain within 1°C (1.8°F) of initial ECT on 6 successive occasions
  1. ECT sensor

MONITOR DESCRIPTION

The ECT sensor is used to monitor the ECT. The ECT sensor has a built-in thermistor with a resistance that varies according to the temperature of the engine coolant. When the ECT is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in the resistance are reflected in the output voltage from the ECT sensor.
The ECM monitors the sensor voltage and uses this value to calculate the ECT. If the sensor output voltage deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the ECT sensor and sets the DTC.
Examples:
  1. Upon starting the engine, the ECT is between 35°C and 60°C (95°F and 140°F). If after driving for 250 seconds, the ECT remains within 3°C (5.4°F) of the starting temperature, the DTC is set (2 trip detection logic).
  2. Upon starting the engine, the ECT is over 60°C (140°F). If after driving for 250 seconds, the ECM remains within 1°C (1.8°F) of the starting temperature, the DTC is set (6 trip detection logic).

INSPECTION PROCEDURE

HINT:
  1. If any of DTCs P0115, P0117, P0118 or P0125 are set simultaneously with DTC P0116, the ECT sensor may have an open or a short circuit. Troubleshoot those DTCs first.
  1. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0116)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Turn the tester ON.

  1. Enter the following menus: Power train / Engine / DTC.

  1. Read the DTC.


Result:

Display (DTC output)
Proceed to
P0116
A
P0116 and other DTCs
B



B
GO TO DTC CHART
A


2.INSPECT THERMOSTAT

  1. Remove the thermostat (Click here).

  1. Check the valve opening temperature of the thermostat.

    Standard:
    80 to 84°C (176 to 183°F)

    HINT:
    In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

  1. Reinstall the thermostat (Click here).



NG
REPLACE THERMOSTAT
OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR