Understanding P0128-00 Chevrolet Error: Troubleshooting with the ECT Sensor and Thermostat Methods

If you are getting a P0128 error code, this article will show you two practical solutions to fix the error at home.

First, use the Zeus app to scan your vehicle and see the error code P0128. This error code indicates that after starting the engine, the powertrain control module has detected that the engine has not reached the required temperature level within a specified amount of time.

Method A: The ECT Sensor

In most cars, the primary Engine Coolant Temperature (ECT) sensor is installed near the thermostat in the cylinder head. Here’s how to proceed:

1. Remove the ECT sensor from the engine.
2. Use a multimeter to conduct a test on the ECT sensor. In an ambient temperature of 68 degrees Fahrenheit, the sensor resistance should be between 2000 ohms and 3000 ohms.
3. If you do not get a reading, this indicates that the ECT sensor is faulty and needs to be replaced.

Method B: The Thermostat

In most cars, the thermostat is placed near the water pump on the cylinder head. Here’s how to proceed:

1. Carefully remove the thermostat from the engine. The engine has to be cool before attempting the process.
2. Install a new thermostat, making sure the short end goes toward the hose and the deep end goes toward the engine.
3. When installing it back to the engine, make sure the jiggle valve is pointed straight up to the top of the engine so the air can get through the system.

After applying these two methods, you can use the Zeus app to clear the error code and rescan your vehicle to ensure everything is functioning properly.

What does the p0128 error code mean?

The p0128 error code means that after starting the engine, the powertrain control module has detected that the engine has not reached the required temperature level within a specified amount of time.

What are the DIY methods to fix the p0128 error code?

There are two DIY methods to fix the p0128 error code: 1. ECT Sensor: Use a multimeter to test the ECT sensor. If the sensor resistance is between 2000 ohms and 3000 ohms, it’s working correctly. If not, it needs to be replaced. 2. Thermostat: Carefully remove the thermostat from the engine and install a new thermostat ensuring the correct orientation.