P0128 on Jeep Renegade
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to Jeep Renegade context without treating complaints as confirmed diagnoses.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
- SAE J2012 Diagnostic Trouble Code Definitions — Generic diagnostic trouble code definition reference for P0128.
- NHTSA recalls, complaints, and manufacturer communications — Used to check public owner complaint context, recall status, and safety-related manufacturer communications by VIN or vehicle.
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What P0128 Means on Your Jeep Renegade
P0128 is a diagnostic trouble code indicating: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature). This code relates to the fuel and air metering system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real Jeep Renegade Owner Reports
Source: NHTSA Complaints Database
"Service engine light came on, code p0128, faulty thermostat. seems to be a common problem."
"Thermostat failure code p0128 appeared and thermostat needed to be replaced. as this vehicle had recall on the cooling fan assembly, this failure is directly related to the malfunction of the fan unit."
"Jeep renegade with only 40k miles (4k out of warranty) and engine coolant thermostat just stopped working. entire housing has to be replaced just to fix the one problem. the problem was made known via service light coming on with "service engine" message appearing on dash."
"I turned on my jeep renegade with the automatic start button in like 30 weather. i drove it down the highway for about 10 minutes and the service engine light turned on. i also had the air bag, brake warning sign turn on. i stopped to put gas and just the service engine light stayed on."
"2016 jeep renegade trailhawk had to replace the thermostat do to code p0128 had 51,000 miles should be a recall on this because it cost me"
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on Jeep Renegade
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
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3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.