Honda Civic · Diagnostic Trouble Code
P0128 — Coolant Thermostat (Coolant Temp Below Regulating Temp)
Quick overview of P0128 on your Honda Civic. Read the full diagnosis guide, then find the repair guides for your vehicle below.
Repair guides that fix P0128
Honda Civic
2016-2021 Honda Civic - Thermostat Replacement
Replacing a thermostat that is stuck open.
Honda Civic
2016-2021 Honda Civic - Coolant Flush
Cooling system service for temp-related codes.
Honda Civic
2016-2021 Honda Civic - Check Engine Light
What that light means and what to check first.
General diagnostic information, not a factory service procedure. If you're unsure, have a qualified technician confirm the diagnosis before buying parts.