P0128 on Cadillac vehicles The engine is not reaching its normal operating temperature in the expected time — usually the thermostat
P0128 is named on 7 Cadillac model years (2017–2023): 9 manufacturer filings and 8 owner reports in NHTSA’s files, across XT5, XT6, CT6.
Which Cadillac model years name P0128
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2017 Cadillac XT5 | Steering | 2 | 4 |
| 2018 Cadillac XT5 | Power Train | — | 4 |
| 2021 Cadillac XT5 | Engine | 2 | — |
| 2021 Cadillac XT6 | Engine | 2 | — |
| 2023 Cadillac XT5 | Steering | 1 | — |
| 2023 Cadillac XT6 | Steering | 1 | — |
| 2020 Cadillac CT6 | Electrical System | 1 | — |
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.
What Cadillac owners said
Source: NHTSA complaint databaseOwners’ own words, scrubbed of anything identifying. Unverified reports filed with NHTSA — what was said, not a finding that it was true.
I had P0128 Code with a warning message " Steering assist is reduced, drive with care"
Cadillac filings that name P0128
Source: NHTSA manufacturer communicationsBulletins and campaigns Cadillac 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.
- 17-NA-158 Service bulletin2017-05-10 · Steering — Hydraulic Power Assist System
- This informational bulletin explains to diagnose and repair the P0128 code before just replacing the power steering gear.
- PIT5967 Service bulletin2023-01-04 · Steering
- This Preliminary information communicates that a vehicle may come to the dealer with a "Service Steering Message" and no codes set that pertain to the steering system. The technician is instructed to look for a P0128 and if it is set to diagnose that code and see if the message will clear.
- 22-NA-054 Service bulletin2022-03-14 · Engine And Engine Cooling
- This technical bulletin provides repair information to correct a customer concern of a Check Engine Lamp Illuminated in the DIC (Driver Information Center), Temperature Gauge Inaccurate, and/or Cooling Fans Continue Running after Vehicle is Turned Off, with DTC P0128 Set.
- 20NA109 Service bulletin2020-05-19 · Electrical System
- This technical bulletin provides a procedure to correct a condition of an MIL Illuminated w/DTC P0128.
What P0128 means
Source: SAE J2012 / OBD-IIThe 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 Cadillac and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs P0128 a known problem on Cadillac vehicles?
It is a documented one: NHTSA's files hold 9 manufacturer filings and 8 owner reports naming P0128 on 7 Cadillac model years (2017–2023). 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 Cadillac models does P0128 appear on most?
2017 XT5 (6 documents), 2018 XT5 (4 documents), 2021 XT5 (2 documents).
Does P0128 on a Cadillac 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.