OBD-II Code: P0128
LOW-MEDIUM SEVERITY
Cooling
Coolant Thermostat Temperature Below Regulating Temp
Can I Drive?
Usually short-distance only; diagnose soon
Stop driving if you notice overheating, bad misfires, loss of power, fuel smell, or flashing warning lights.
Common Causes
Sticking thermostat, low coolant, faulty coolant temperature sensor
DIY Checks
Check coolant level; thermostat may be sticking open
Mechanic Questions to Ask
Thermostat replacement, coolant flush
Disclaimer: OBD code information is educational, not a professional diagnosis. The same code can have different causes depending on vehicle, mileage, maintenance history, and related codes. Always verify with a qualified mechanic.