What P0128 means
Termostato del refrigerante del motor (temperatura del refrigerante inferior a la temperatura de regulación del termostato)
Common causes (general)
Before spending money on parts, verify the code with a scan tool and read freeze frame data. Freeze frame captures every sensor value at the moment the code set — this is often enough to figure out the root cause without further testing.
Manufacturer-specific descriptions
Different manufacturers use this code for slightly different failure modes. Here's what your specific make means by P0128:
| AUDI | Defective Engine Thermostat, Defective Engine Coolant Temperature Sensor, Defective Intake Air Temperature Sensor, Defective Cooling System, Low Engine Coolant, Dirty Engine Coolant causing incorrect Coolant Temperature Sensor readings, Defective/always running Engine Cooling fan(s) |
| BMW | Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) |
| FORD | Coolant Thermostat Malfunction |
| HONDA | Cooling System Malfunction |
| MITSUBISHI | Coolant thermostat |
| VOLKSWAGEN | Coolant Thermostat |
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