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Home >> Lexus >> 2017 >> LS 460 Base, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System - Diagnostic Codes (P0010-P0230) >> SFI System >> DTC P0115: Engine Coolant Temperature Circuit; DTC P0117: Engine Coolant Temperature Circuit Low Input; DTC P0118: Engine Coolant Temperature Circuit High Input [09/2015 - ] >> 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 [09/2015 - ]: Description

A thermistor, whose resistance value varies according to the ECT, is built into the Engine Coolant Temperature (ECT) sensor.

The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.

HINT: 

When DTC P0115, P0117 or P0118 is 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.

DTC No. DTC Detection Condition Trouble Area
P0115 Open or short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
  • Open or short in ECT sensor circuit
  • ECT sensor
  • ECM
P0117 Short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
  • Short in ECT sensor circuit
  • ECT sensor
  • ECM
P0118 Open in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
  • Open in ECT sensor circuit
  • ECT sensor
  • ECM

HINT: 

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

Temperature Displayed Malfunction
-40°C (-40°F) Open circuit
140°C (284°F) or higher Short circuit