P0116

2AZ-FE ENGINE CONTROL: SFI SYSTEM: P0116: Engine Coolant Temperature Circuit Range / Performance Problem

DTC P0116 - Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

A thermistor, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor.
The structure of the sensor and its connection to the ECM are similar to that of the intake air temperature sensor.
HINT: When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

HINT: When any of these DTCs are set, check the engine coolant temperature by entering the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.










*: Only Mexico models.

MONITOR DESCRIPTION

The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the engine coolant. When the engine coolant temperature becomes low, the resistance of the thermistor increases. When the temperature becomes high, the resistance drops. These variations in the resistance are reflected in the voltage output from the engine coolant temperature sensor.
The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. If the sensor voltage output deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the engine coolant temperature sensor and sets the DTC.

Examples:

- Upon starting the engine, the engine coolant temperature is between 35°C and 60°C (95°F and 140°F). If the engine coolant temperature remains within 3°C (37°F) of the stating temperature after driving for 250 seconds, the DTC is set (2 trip detection logic).
- Upon starting the engine, the engine coolant temperature is over 60°C (140°F). If the engine coolant temperature remains within 1°C (34°F) of the starting temperature after driving for 250 seconds, the DTC is set (6 trip detection logic).

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

Engine Coolant Temperature Sensor Cold Start Monitor





Engine Coolant Temperature Sensor Soak Monitor





TYPICAL MALFUNCTION THRESHOLDS

Engine Coolant Temperature Sensor Cold Start Monitor





Engine Coolant Temperature Sensor Soak Monitor





COMPONENT OPERATING RANGE





INSPECTION PROCEDURE
HINT:
- If any of DTCs P0115, P0117, P0118 or P0125 are set simultaneously with DTC P0116, the engine coolant temperature sensor may have an open or a short circuit. Troubleshoot those DTCs first.
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result:






B -- GO TO DTC CHART
A -- Continue to next step.
2. INSPECT THERMOSTAT
(a) Remove the thermostat Removal.
(b) Measure the valve opening temperature of the thermostat.
Standard Value:
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.
(c) Reinstall the thermostat Installation.
NG -- REPLACE THERMOSTAT
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR