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Home >> Mazda >> 2017 >> 3 Sport, 4D Hatchback, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control (2 Of 5) >> DTC P0118; Pcm ECT Sensor No. 1 Circuit High Input >> Notes

DTC P0118; Pcm ECT Sensor No. 1 Circuit High Input: Notes

DETECTION CONDITION & POSSIBLE CAUSE

DTC P0118:00 ECT sensor No. 1 circuit high input
DETECTION CONDITION
  • The PCM monitors the ECT sensor No. 1 signal. If the PCM detects that the ECT sensor No. 1 voltage at the PCM terminal 1AK is above 4.9 V for 5 s, the PCM determines that the ECT sensor No. 1 circuit has a malfunction.

    Diagnostic support note

  • This is a continuous monitor (engine cooling system).
  • The check engine light illuminates if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
  • DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION
  • Fixes the water temperature for the engine control at 40 °C {104 °F}, and for the idle air control at 80 °C {176 °F}.
  • Operates the cooling fan (high speed rotation).
  • Inhibits the fuel cut control during shift change.
POSSIBLE CAUSE
  • ECT sensor No. 1 connector or terminals malfunction
  • ECT sensor No. 1 malfunction
  • PCM connector or terminals malfunction
  • Short to power supply in wiring harness between ECT sensor No. 1 terminal A and PCM terminal 1AK
  • Open circuit in wiring harness between the following terminals:
    • ECT sensor No. 1 terminal A-PCM terminal 1AK
      • ECT sensor No. 1 terminal B-PCM terminal 1AM
  • PCM malfunction
G11550273
CAUTION:
  • Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.

Related PIDs

Item (definition) Unit/Condition Definition Condition/Specification (Reference)
ECT °C, °F Engine coolant temperature
  • Displays ECT
V ECT sensor No. 1 voltage
  • ECT is 20 °C {68 °F}: Approx. 3.10 V
  • ECT is 40 °C {104 °F}: Approx. 2.16 V
  • ECT is 60 °C {140 °F}: Approx. 1.40 V
  • ECT is 80 °C {176 °F}: Approx. 0.87 V
  • ECT is 100 °C {212 °F}: Approx. 0.54 V