HomeP0128 · Coolant temperature below thermostat regulating temperature
Powertrain

P0128

Coolant temperature below thermostat regulating temperature

P0128
Reference meaning

What does this code mean?

The warm-up performance did not meet the monitor's expectation. Check coolant level only when the engine is cool, compare temperature readings from a cold start, and assess the thermostat and cooling-fan operation. Climate, sensor accuracy and vehicle calibration matter. Never open a hot pressurised cooling system.

A code identifies a detected condition, not a part that must automatically be replaced.

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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

Manufacturer communications

2

Original wording in English

NTB21-006A

NISSAN

Reported code forms P0128

MIL ON WITH DTC P0128 STORED This bulletin has been amended. See AMENDMENT HISTORY on the last page. Please discard previous versions of this bulletin.

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NTB21-006

NISSAN

Reported code forms P0128

MIL ON WITH DTC P0128 STORED IF YOU CONFIRM The MIL is ON and DTC P0128 (THERMSTAT FNCTN) is stored in the ECM, AND There are no drivability concerns. ACTION 1. Confirm the current ECM part number. 2. Reprogram the ECM,…

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Check vehicle applicability

1

A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

Historical vehicle association; OBD-II compatibility is not established by this record.

MakeModelModel year
NissanVERSA2021

Historical records · 4 · Historical vehicle association; OBD-II compatibility is not established by this record.

Before replacing a part

Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.

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Sources and interpretation

These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.

  1. 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗

    Ford Motor Company · PDF page(s) 71 ·

Source check date · 2026-10-27

Can I keep driving?

A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.