P0116

2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P0116: Engine Coolant Temperature Circuit Range / Performance Problem
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 hybrid vehicle control ECU are the same as those of the intake air temperature sensor.

HINT
When any of DTCs P0115, P0117 and P0118 are set, the hybrid vehicle control ECU enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the hybrid vehicle control ECU. 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.





MONITOR DESCRIPTION

Engine Coolant Temperature Sensor Cold Start Monitor

The monitor runs when the engine is started cold. If the change in engine coolant temperature sensor output until the engine warmed up completely is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is set.

Engine Coolant Temperature Sensor Soak Monitor

The hybrid vehicle control ECU compares the engine coolant temperature when the warmed engine is stopped and when the engine is started on the next trip after more than 5 hours has elapsed since the engine was stopped. If the change in engine coolant temperature sensor output is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is set.

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





CONFIRMATION DRIVING PATTERN





- Connect the Techstream to the DLC3.

- Turn the power switch on (IG) and turn the Techstream on.

- Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.

- Check that the engine coolant temperature is 60°C (140°F) or less.

- Clear the DTCs DTC Check / Clear.

- Turn the power switch off and wait for at least 30 seconds.

- Turn the power switch on (IG) and turn the Techstream on [A].

- Put the engine in inspection mode Component Tests and General Diagnostics.

- Start the engine and idle it for 5 minutes or more [B].

HINT
If the engine coolant temperature does not change by 5°C (9°F) or higher, the engine coolant temperature sensor is malfunctioning. It is not necessary to continue this procedure.

- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

- Read the pending DTC [C].

HINT
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

- Input the DTC: P0116.

- Check the DTC judgment result.





HINT
If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [D] and [E].

- Drive the vehicle at 25 mph (40 km/h) or more for a total of 5 minutes or more [D].

HINT
In the event of the drive pattern being interrupted (possibly due to factors such as traffic conditions), the drive pattern can be resumed.

- Check the DTC judgment result again [E].

HINT
If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [D] and [E] again.

INSPECTION PROCEDURE

HINT
- If any of DTCs P0115, P0117 and P0118 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 hybrid vehicle control ECU 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 power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTCs.

Result:





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

B -- GO TO DTC CHART SFI System
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 Removal

OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal