P0128 on a 2013 Ford Escape

P0128 means the engine warmed up slower than expected or stayed cooler than the computer expected.

Not your vehicle? See general P0128 info.

Most common causes on the 2013 Ford Escape

Ranked from 2,743 NHTSA owner complaints filed for this vehicle.

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1
Coolant intrusion into engine cylinders
High severity
Coolant leaking into the engine cylinders (often due to a cracked cylinder head or block) causes rapid coolant loss, misfires, and overheating, which can disrupt normal temperature readings.
Reported in 9 NHTSA complaints
2
Coolant leak from thermostat housing/water outlet
High severity
A fast coolant leak from the thermostat housing or water outlet can lead to low coolant levels and overheating, which may trigger temperature-related codes.
Reported in 1 NHTSA complaint
3
Faulty coolant bypass valve
Medium severity
A broken coolant bypass valve can disrupt the normal flow of coolant, leading to temperature regulation issues and potential leaks.
Reported in 1 NHTSA complaint
4
Faulty thermostat
Medium severity
The thermostat may be stuck open, preventing the engine from reaching its optimal operating temperature. This is a primary cause for code P0128.
Common cause
5
Low engine coolant level
Medium severity
Insufficient coolant can prevent the engine coolant temperature sensor from getting an accurate reading, triggering the code.
Common cause
6
Faulty Engine Coolant Temperature (ECT) sensor
Low severity
A malfunctioning ECT sensor can send incorrect temperature readings to the PCM, falsely indicating that the engine has not reached operating temperature.
Common cause

These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0128 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Weak cabin heat
Poor fuel economy
Temperature gauge low
Long warm-up time

What to check before replacing parts

Check coolant level when the engine is cold

Look for: Low coolant reduces the system's ability to reach and hold operating temperature — top off and recheck before assuming the thermostat or sensor is at fault.

Compare scan-tool coolant temperature to actual warm-up time

Look for: An engine that takes noticeably longer than normal to reach operating temperature (or never gets there) on the scan tool, with normal coolant level, points to the thermostat rather than the sensor.

Inspect thermostat operation

Look for: A thermostat stuck open (or opening at the wrong temperature) lets coolant circulate through the radiator too early, keeping the engine running cooler than it should — this is the most common cause of this code.

Check cooling fan command

Look for: A fan that runs constantly or turns on too early (commanded on when temperature is still low) keeps the engine from warming up normally, mimicking a stuck-open thermostat.

Inspect coolant temperature sensor data

Look for: A sensor reading that doesn't rise smoothly with actual engine warm-up, or that reads implausibly low compared to how the engine feels/behaves, points to a sensor or wiring fault rather than a true cooling problem.

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