DTC P0118-00: ECT Sensor Circuit High Input: Notes

DTC DETECTION DESCRIPTION

DTC P0118:00	ECT sensor circuit high input
DETECTION CONDITION	The PCM monitors the ECT sensor signal. If the PCM detects that the ECT sensor voltage at the PCM terminal 1AK is above 4.9 V for 5 s, the PCM determines that the ECT sensor 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/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 connector or terminals malfunction ECT sensor malfunction PCM connector or terminals malfunction Short to power supply in wiring harness between ECT sensor terminal A and PCM terminal 1AK Open circuit in wiring harness between the following terminals: ECT sensor terminal A-PCM terminal 1AK ECT sensor terminal B-PCM terminal 1AM PCM malfunction

Fig 1: ECT Sensor Circuit Diagram

Courtesy of MAZDA MOTORS CORP.

CAUTION:

• Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.

PATRS DESCRIPTION

Item	Definition	Unit	Condition/Specification
ECT	Engine coolant temperature input from ECT sensor	°C, °F	Displays ECT
	ECT sensor voltage	V	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