Cooling System Malfunction
Table of contents
P0128 HONDA Possible Causes
- Low engine coolant level
- Insufficient warm uptime
- Leaking or stuck open thermostat
- Faulty engine coolant temperature sensor
- Engine coolant temperature sensor harness is open or shorted
- Engine coolant temperature sensor circuit poor electrical connection
How do I fix code P0128 HONDA?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
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Cost of diagnosing the P0128 HONDA code
The cost of diagnosing the P0128 HONDA code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0128 HONDA Description
The Engine Coolant Thermistor (ECT) is a 2-wire thermistor. As Engine coolant temperature increases, thermistor resistance & signal voltage decreases. The Engine Control Module (ECM) monitors ECT voltage to help determine injector pulse width, ignition timing, and idle control. The Transmission Control Module (TCM)/ECM uses ECT voltage for shift timing & quality. The Diagnostic Trouble Code (DTC) indicates that the thermostat monitor has not achieved the required engine operating temperature within a specified amount of time after starting the engine.