P0116

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

DTC P0116 - Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.
The structure of the sensor and connection to the ECM is the same as the Intake Air Temperature (IAT) sensor.

HINT: When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the ECT 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 ECT by electing the following menus on the Techstream: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.






MONITOR DESCRIPTION

ECT sensor cold start monitor

- When a cold engine start is performed and then the engine is warmed up, if the ECT sensor value does not change, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.

ECT sensor soak monitor

- If the ECT sensor value does not change after the warmed up engine is stopped and then the next cold engine start is performed, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





Cold start monitor:





Soak monitor:





TYPICAL MALFUNCTION THRESHOLDS

Cold start monitor:





Soak monitor:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT:
- 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.
- Read freeze frame data using the Techstream. 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.

PROCEDURE

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





HINT: If any DTCs other than P0116 are output, troubleshoot those DTCs first.

B -- GO TO RELEVANT DTC CHART
A -- Continue to next step.
2. INSPECT THERMOSTAT
(a) Remove the thermostat (Removal).
(b) Check the valve opening temperature of the thermostat (Testing and Inspection).
Standard opening temperature:
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