RX400h · Service Manual ENGINE

P0116 Case1:Engine Coolant Temperature (ECT) between 35°C and 60°C (95°F and 140°F) when engine started, and...

Diagnostic trouble codes

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 its connection to the ECM (Included in HV Control ECU) are the same as those of the Intake Air Temperature (IAT) sensor.
DTC No.
 DTC Detection Condition
 Trouble Area
P0116
  1. Case1:
    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):
    1. Vehicle driven at varying speeds (accelerated and decelerated)
    2. ECT remains within 3°C (5.4°F) of initial ECT
  2. Case2:
    ECT more than 60°C (140°F) when engine started, and conditions (a) and (b) met (6 trip detection logic):
    1. Vehicle driven at varying speeds (accelerated and decelerated)
    2. ECT measurements remain within 1°C (1.8°F) of initial ECT on 6 successive occasions
  1. Thermostat
  2. ECT sensor

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.
  2. Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 ignition switch ON.

  1. Turn the tester ON.

  1. Enter the following menus: Powertrain / 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


← P0115 Step 1P0120 →