Honda Accord Quiz
Engine Control

Engine Coolant Temperature (ECT) Sensor Inspection and Replacement

In this manual: Engine Control
Owner's Manual — 80Maintenance and Adjustments — 43Four-Cylinder Engines — 27V6 Engines — 34Engine General Overhaul and Major Repair — 35Cooling and Heating Systems — 29Fuel and Exhaust Systems — 21Engine Electrical Equipment — 23Engine Control — 315-speed manual transmission (MT) — 74-speed automatic transmission (AT) — 14Clutch and Drive Shafts — 22Brake System — 23Suspension and Steering — 31Body — 41Body Electrical Equipment — 36Electrical Circuit Diagrams — 11
~2min read

INSPECTION
PROCEDURE

1. The ECT sensor is a thermistor (a resistor whose resistance changes with temperature). The sensor resistance directly affects the signal voltage it sends to the PCM. As temperature DECREASES, sensor resistance INCREASES, and vice versa. A faulty ECT sensor results in diagnostic trouble codes P0116, P0117 or P0118 being stored in the OBD system memory.
2. To check ECT sensor operation, measure its resistance. Locate the sensor and disconnect the wiring harness from it.

3. Подключите омметр к двум клеммам сборки датчика. При температуре около 20°С

3. Connect an ohmmeter to the two terminals of the sensor assembly. At a temperature of about 20°C, the meter should read approximately 2500 ÷ 3500 Ohms. Now start the engine and warm it up to normal operating temperature (alternatively, the sensor may be removed and heated to the required temperature in a hot water bath). The sensor resistance should drop, and at a temperature of about 83°C it should be 250 ÷ 350 Ohms. If the results of this check are unsatisfactory, replace the ECT sensor.

If the engine ran with the sensor disconnected, be sure to clear the On-Board Diagnostic (OBD) system memory (refer to On-Board Diagnostic (OBD) System - Operation and Trouble Codes).
REPLACEMENT
PROCEDURE


Before starting the procedure, allow the engine to cool down completely.
1. Disconnect the negative battery cable.

If the vehicle is equipped with an audio system with an anti-theft code, make sure you have the correct code to reactivate the audio system before disconnecting the battery!
2. Before installing the new sensor, wrap its threaded portion with PTFE sealing tape (thread sealant tape).
3. Depress the locking tab, disconnect the wiring, then carefully unscrew the sensor. To minimize coolant loss, install the replacement sensor as quickly as possible.

Handle the ECT sensor carefully, as damage to it can significantly affect the operation of the fuel system as a whole.
4. Install in the reverse order. Finally, check the coolant level and, if necessary, top up (refer to Maintenance and Adjustments chapter).

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