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Home›Trouble codes›P0128› Ram
Diagnostic trouble code · Ram

P0128 on Ram vehicles The engine is not reaching its normal operating temperature in the expected time — usually the thermostat

P0128 is named on 12 Ram model years (2016–2024): 27 manufacturer filings and 0 owner reports in NHTSA’s files, across 3500, 1500, 2500, Promaster City, ProMaster.

Powertrain 12 model years 27 manufacturer filings

Which Ram model years name P0128

Source: NHTSA manufacturer communications and complaints
Model yearFiled underBulletinsOwner reports
2016 Ram 3500Power Train6—
2021 Ram 1500Engine5—
2020 Ram 1500Engine4—
2016 Ram 2500Engine3—
2016 Ram Promaster CityPower Train2—
2024 Ram 1500Equipment1—
2024 Ram ProMasterEquipment1—
2023 Ram 1500Equipment1—
2023 Ram ProMasterEquipment1—
2022 Ram ProMasterEquipment1—
2021 Ram ProMasterEquipment1—
2017 Ram Promaster CityPower Train1—

A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.

Engine 11 Equipment 7 Power Train 5 Fuel/Propulsion System 1
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Ram filings that name P0128

Source: NHTSA manufacturer communications

Bulletins and campaigns Ram filed with NHTSA whose summary names P0128. Quote the document number at the service desk — it is a diagnosis the maker has already written down.

What P0128 means

Source: SAE J2012 / OBD-II

The engine is not reaching its normal operating temperature in the expected time — usually the thermostat.

A stored code names the test that failed, never the part that caused it. The record above is what Ram and its owners have filed about it; the code’s page across every make has the whole file.

From here
Get a model's new bulletins by email See what owners reported Look up a bulletin by its number Watch a VIN for new recalls

Common questions

Source: NHTSA files and the OBD-II standard

Is P0128 a known problem on Ram vehicles?

It is a documented one: NHTSA's files hold 27 manufacturer filings and 0 owner reports naming P0128 on 12 Ram model years (2016–2024). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.

Which Ram models does P0128 appear on most?

2016 3500 (6 documents), 2021 1500 (5 documents), 2020 1500 (4 documents).

Does P0128 on a Ram mean it is recalled?

No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.

Where to go next

pages beside this code
Filed alongside P0300 Another code that appears in the same filings and owner reports as P0128.Filed alongside P0455 Another code that appears in the same filings and owner reports as P0128.Vehicle 2016 Ram 3500 The model year P0128 is filed against most often.The data Trouble codes by API GET /v1/dtc joins every code to bulletins and owner reports — free tier, no card.