What is P0128?

Is Your Engine Coolant Warm or Hot?

Your engine light is illuminating. Check the engine! Behind the scenes, a computer is delivering a P0128 code. What does this code mean? Do you write C and C++? Your vehicle just spits a code back at you, telling you the line of code in your vehicle has an error. Most cars use C and C++ programming languages to transmit messages. When P0128 displays, it’s a diagnostic trouble code (DTC) for “Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature).”

What if P0128 shows up in summer when it usually shows up in the winter months? What do you do? Contact Cottman Transmission in Cincinnati, OH at 513-688-7522 or stop by the shop at 665 Cincinnati Batavia Pike Cincinnati, OH 45245 and let the P0128 experts take over.

When you take immediate action with a P0128 code, there is usually minimal engine damage. When left unattended, a P0128 may result in engine damage from water contamination of the oil, causing deterioration and engine damage. P0128 lights up when the coolant isn’t getting hot enough. The condensation in the engine cannot burn off, and water could end up in the oil.

P0128 means the engine is not getting warm enough, fast enough. The engine operating temperature is not reaching the specified temperature within the designated time programmed to do so. The Engine Control Module (ECM) determines the time necessary to reach ambient temperature.

The engine thermostat could be stuck in the open position or opening prematurely. The second possibility is that the engine coolant temperature gauge reaches its peak. This may be due to a heater not getting hot enough or the car taking too long to warm up.

Cottman Transmissions will check the radiator and hoses and check for correct temperatures. When the thermostat opens extremely hot, the coolant should be flowing, and when the hoses are not hot, there could be an issue. If it gets hot immediately, we check the coolant temperature sensor.

When P0128 shows up, the usual steps are to replace the thermostat, the coolant temperature sensor, or possibly the wiring and connector associated with the sensor. Cottman Transmission is always ready to help with any vehicle issue. We service all makes and models and will be honored to welcome you into our circle of influence. Please contact Cottman Transmission today at 513-688-7522 or drive up and ask one of our technicians how we can help you at 665 Cincinnati Batavia Pike Cincinnati, OH 45245. We’ll leave the door open!