P0128 — Coolant temperature below thermostat regulating temperature (thermostat stuck open).

Code P0128 is a standard OBD-II diagnostic trouble code: Coolant temperature below thermostat regulating temperature (thermostat stuck open).

In ProblemsByVin's analysis of the NHTSA owner-complaint record, owners cite P0128 across 52 vehicle failure patterns. Diagnostic codes in complaints are reported by owners and are unverified — they point to where this code shows up, not a confirmed diagnosis. Open a page below for the full pattern (symptoms, mileage, repair costs owners cite).

Vehicles where owners report P0128 52 patterns

2022 GMC Yukon

engine — Complete Engine Failure — Bearing/Crankshaft Damage

2021 Chevrolet Blazer

electrical — Engine Coolant Temperature (ECT) Sensor / Thermostat Malfunction

2021 Chevrolet Blazer

steering — Steering Assist Reduced warning message with actual steering loss or stiffness

2021 GMC Acadia

steering — Engine Coolant Thermostat Failure

2021 Jeep Cherokee

electrical — Uncommanded/Ghost Braking at Speed

2020 Chevrolet Blazer

powertrain — Thermostat failure with cooling system malfunction

2020 Chevrolet Blazer

electrical — Engine Coolant Temperature Sensor / Thermostat System Failure

2020 Chevrolet Blazer

engine — Thermostat stuck open or closed

2020 Chevrolet Blazer

steering — Coolant Temperature Sensor / Thermostat Circuit Malfunction

2020 GMC Acadia

electrical — Engine Coolant Temperature Sensor Failure (P0128)

2020 Jeep Renegade

electrical — Intermittent engine stalling with false/multiple warning lights

2020 Kia Telluride

engine — Oil filter housing leak (plastic housing failure)

2020 Subaru Forester

engine — Thermo Control Valve (Engine Coolant Bypass Valve) Failure

2019 Chevrolet Blazer

powertrain — Thermostat and Coolant Temperature Sensor Faults

2019 Chevrolet Blazer

steering — Steering Assist Reduced / Power Steering Loss

2019 Chevrolet Blazer

electrical — Coolant temperature sensor/thermostat wiring interference

2019 GMC Acadia

steering — Thermostat Failure and Steering Assist Disable

2019 GMC Acadia

engine — Thermostat / Water Outlet Assembly Failure

2019 Kia Optima

engine — Excessive Oil Consumption

2018 Cadillac XT5

powertrain — Coolant thermostat failure with check engine codes P0128

2018 Cadillac XT5

steering — Steering Assist Reduced warning with hard steering

2018 Dodge Grand Caravan

electrical — Engine Stall / Loss of Power While Driving

2018 GMC Acadia

steering — Steering Assist Reduced / Power Steering Assist Failure

2018 Hyundai Elantra

engine — ECM/software issues causing stalling and misfire

2018 Hyundai Elantra

electrical — Engine Stalling & Loss of Power

2017 Cadillac XT5

steering — Steering Assist Reduced Message / Power Steering Failure

2017 GMC Acadia

steering — Steering assist loss / power steering system failure

2017 Honda Civic

electrical — A/C Compressor Lock-Up and Engine Stall

2017 Hyundai Elantra

engine — Coolant Thermostat Failure

2016 Chevrolet Camaro

powertrain — 8-Speed Automatic Transmission Shuddering and Harsh Shifting

2016 Chrysler Town and Country

powertrain — Transmission Shifting Abnormalities / Rough Shift / Hesitation

2016 Dodge Grand Caravan

steering — Steering wheel lockup with loss of power assist

2016 Jeep Renegade

engine — Cooling fan failure and overheating

2016 Jeep Renegade

airbags — Service Airbag Light with Concurrent Electrical Warnings

2016 Mazda CX-9

engine — Cracked cylinder head with coolant leak

2014 Chrysler 200

powertrain — Transmission Jerking and Lurching During Shifting

2014 GMC Acadia

steering — Power steering pump failure

2013 Chevrolet Cruze

steering — Intermittent Power Steering Loss

2013 Ford Escape

engine — Engine overheating with coolant loss—limp mode and shutdown

2013 Jeep Grand Cherokee

electrical — Check Engine Light with Multiple / Intermittent Codes

2012 Buick LaCrosse

suspension — Camshaft timing solenoid malfunction

2012 Chevrolet Equinox

powertrain — Excessive Oil Consumption & Timing Chain Failure

2012 Dodge Grand Caravan

electrical — TIPM failure causing no-start/intermittent start

2012 Dodge Charger

engine — Thermostat/Coolant Issues

2011 Subaru Outback

electrical — Stalling and loss of power while driving

2008 Chevrolet Silverado

engine — Sudden engine stall and loss of power

2008 Ford Fusion

powertrain — Ignition coil and PCM failure

2006 Dodge Charger

electrical — Stalling while driving — intermittent, multiple speeds

2006 Dodge Durango

engine — Engine stalling without warning

2006 Pontiac Grand Prix

engine — Dexcool coolant degradation and gasket failure

2005 Chevrolet Aveo

engine — Plastic thermostat housing cracking/splitting

2005 GMC Envoy

engine — Thermostat malfunction

Codes are pulled from what owners wrote in their NHTSA filings — they're allegations, not a shop diagnosis. Always confirm with a live scan. Browse all diagnostic codes →