2021-2024 Jeep, Dodge, RAM P0128 Thermostat Issue
A technical service bulletin (TSB S2309000014) has been issued for 2021-2024 Jeep, Dodge, and RAM vehicles equipped with the 3.6L Pentastar engine, addressing diagnostic trouble code P0128 related to the thermostat assembly.
Marcus Weber2021 Jeep Wrangler
Also applies to
- Jeep Gladiator
- 2021–2024
- Jeep Grand Cherokee
- 2021–2024
- Jeep Grand Wagoneer
- 2022–2024
- Jeep Wagoneer
- 2022–2024
- Jeep Wrangler
- 2022–2024
- Dodge Durango
- 2021, 2022, 2024
- Ram 1500
- 2021–2024
▸ Show 1 more▾ Show fewer
Owners of 2021-2024 Jeep, Dodge, and RAM vehicles equipped with the 3.6L Pentastar engine may encounter a "P0128 failure code" related to the thermostat assembly. This issue is addressed by Technical Service Bulletin (TSB) S2309000014, which provides guidance for diagnosing and resolving the problem.
The TSB specifically targets vehicles that display the P0128 code, indicating that the engine coolant temperature is not reaching the necessary operating temperature within a specified time.
Symptoms
The primary symptom associated with this bulletin is the illumination of the Malfunction Indicator Lamp (MIL) due to the presence of diagnostic trouble code P0128. This code signifies that the engine coolant temperature is too low, which can impact engine efficiency and emissions.
Fault Codes / DTCs
This bulletin specifically addresses the following Diagnostic Trouble Code (DTC):
- P0128: Engine Coolant Temperature is Too Low
Diagnosis
Before any parts are replaced, technicians are instructed to perform a thorough inspection. The TSB emphasizes the importance of following the inspection instructions provided in the latest version of Star Online Publication S2309000014. This step is crucial to accurately diagnose the root cause of the P0128 code.
Repair Procedure Summary
For affected vehicles displaying the Jeep P0128 thermostat issue, the repair involves a potential replacement of the thermostat assembly. However, this replacement should only occur after the detailed inspection procedures outlined in TSB S2309000014 have been completed and confirm the need for a new thermostat. The TSB focuses on ensuring that unnecessary thermostat replacements are avoided.
Important Warnings
Owners and technicians should be aware of a critical instruction from the manufacturer: "PRIOR TO PERFORMING ANY THERMOSTAT REPLACEMENT, PROCEED WITH INSPECTION INSTRUCTIONS FROM THE LATEST VERSION OF STAR ONLINE PUBLICATION S2309000014." This means a direct replacement of the thermostat without proper diagnostic inspection is not recommended and may not resolve the underlying issue.
Owner Action
If your 2021-2024 Jeep, Dodge, or RAM vehicle with the 3.6L Pentastar engine exhibits a check engine light and you suspect a Jeep P0128 thermostat problem, it is recommended to visit an authorized dealer. They will be able to perform the necessary diagnostic inspections and apply the appropriate repair as outlined in TSB S2309000014.
Source: NHTSA ID: 10251767
Frequently Asked Questions
- What does the P0128 code mean for my Jeep, Dodge, or RAM?
- The P0128 diagnostic trouble code (DTC) indicates that your vehicle's engine coolant temperature is too low. This means the engine is not reaching its optimal operating temperature within the expected time frame.
- Which vehicles are affected by TSB S2309000014?
- TSB S2309000014 applies to 2021-2024 Jeep, Dodge, and RAM vehicles equipped with the 3.6L Pentastar engine that are experiencing the P0128 failure code.
- Should I replace the thermostat immediately if I see a P0128 code?
- No, the manufacturer specifically advises against immediate thermostat replacement. Before any replacement, technicians must follow detailed inspection instructions from the latest version of Star Online Publication S2309000014 to accurately diagnose the cause of the Jeep P0128 thermostat issue.
- What should I do if my vehicle has a P0128 code?
- If your vehicle displays a P0128 code, you should schedule an appointment with an authorized dealer. They have access to the specific diagnostic procedures and the TSB S2309000014 to correctly identify and resolve the problem.
Related Articles
2021 Jeep Wrangler Health Check: Recalls and Bulletins
The 2021 Jeep Wrangler has faced several significant issues, including recalls for potential engine stalls, high voltage battery fires in 4Xe models, and instrument panel failures. Owners should be aware of these safety concerns and numerous service bulletins addressing various electrical, engine…
2021-2026 Stellantis KeyFOB Low Battery DTCs B1A10-00
Stellantis TSB S2608000010 addresses diagnostic trouble codes B1A10-00 through B1A17-00 related to KeyFOB low battery conditions in 2021-2026 Chrysler, Dodge, Jeep, and RAM vehicles. Symptoms include inoperable remote keyless entry or passive start. Learn the recommended fix.
2021-2026 Jeep Wrangler/Gladiator Handle Release Parts
A Quality Inspection Request has been issued for specific 'HANDLE - INSIDE RELEASE' parts (68282334AD, 68282335AD, 68282336AD, 68282337AD, 68323950AD, 68323951AD) affecting 2021-2026 Jeep Wrangler and Gladiator vehicles. Parts built before August 7, 2025, are suspect and require return.
2021-2026 Jeep Wrangler/Gladiator Filiform Corrosion TSB
FCA Caribbean Warranty Bulletin ID-25-11 Rev. B provides updated procedures for diagnosing and repairing aluminum filiform corrosion on various body panels for 2021-2026 Jeep Wrangler and Gladiator vehicles, including specific labor operations and Vehicle Digital Imaging (VDI) pre-approval…
2021-2026 Jeep Wrangler/Gladiator Filiform Corrosion Warranty
Jeep Warranty Bulletin D-25-15 (Rev. B) addresses aluminum filiform corrosion on 2021-2026 Jeep Wrangler and Gladiator vehicles. This bulletin updates the repair process for inner door shells and clarifies the Vehicle Digital Imaging (VDI) pre-approval requirements for paint repairs and panel…
Leave a comment
Comments are moderated and may take a moment to appear. Only your first name and the initial of your last name are shown publicly.
Comments
Be the first to comment.