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Home >> Lexus >> 2015 >> RC 350 Base, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (2GR-FSE) - Diagnostic Codes (1 Of 5) >> SFI System >> DTC P0115: Engine Coolant Temperature Circuit; DTC P0117: Engine Coolant Temperature Circuit Low Input; DTC P0118: Engine Coolant Temperature Circuit High Input [09/2014 - 11/2017] >> Description
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DTC P0115: Engine Coolant Temperature Circuit; DTC P0117: Engine Coolant Temperature Circuit Low Input; DTC P0118: Engine Coolant Temperature Circuit High Input [09/2014 - 11/2017]: 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 the same as those of the intake air temperature sensor.

HINT: 

When DTC P0115, P0117 or P0118 is stored, 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.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0115 Engine Coolant Temperature Circuit An open or short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).
  • Open or short in engine coolant temperature sensor circuit
  • Engine coolant temperature sensor
  • ECM
Comes on DTC stored
P0117 Engine Coolant Temperature Circuit Low Input A short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).
  • Short in engine coolant temperature sensor circuit
  • Engine coolant temperature sensor
  • ECM
Comes on DTC stored
P0118 Engine Coolant Temperature Circuit High Input An open in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).
  • Open in engine coolant temperature sensor circuit
  • Engine coolant temperature sensor
  • ECM
Comes on DTC stored

HINT: 

When any of these DTCs are output, check the engine coolant temperature using the Techstream. Enter the following menus on the Techstream: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.

Temperature Displayed Malfunction
-40°C (-40°F) Open circuit
Higher than 135°C (275°F) Short circuit