P0128 code i'm getting a P0128 code on my 2002 Chevy Impala, but i'm not sure whether its the coolant temperature sensor. The code indicates that theres a improper coolant temperature, can anyone shed some light on this situation i have?

This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.
A code P0128 may mean that one or more of the following has happened:

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

Past experience indicates that the most likely solution is to replace the thermostat. However here are some suggestions on troubleshooting and repairing a P0128 OBD-II code:

• Verify coolant strength & level
• Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
• Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
• Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
• If the above items check out good, replace the thermostat

you have all ready replaced the thermostat with the proper temperature opening thermostat(hopefully) and coolant sensor, you say you have to refill the coolant every 2 weeks this indicates that you either have a coolant leak that needs to be checked out and repaired or you are burning coolant which indicates a possible head gasket problem which will have to be checked. a low coolant level will set this code as there is not enough coolant in the engine to get the engine to operating temperature and stay there. these last suggestions is where I would start to look.

code P0128 ECT ( electronic coolant temperature ) engine temperature to low ( replace thermostat ).

code P0300 engine miss fire detected ( replace spark plugs and spark plug wires )

code P0506 IAC ( idle air control ) system idle to low ( clean the IAC valve if problem persists replace the IAC valve )

P0101 is the Mass Air Flow Sensor error,
http://www.obd-codes.com/p0101


P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature

This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.

A code P0128 may mean that one or more of the following has happened:

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

Past experience indicates that the most likely solution is to replace the thermostat. However here are some suggestions on troubleshooting and repairing a P0128 OBD-II code:

• Verify coolant strength & level
• Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
• Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
• Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
• If the above items check out good, replace the thermostat

REFERENCE: http://www.obd-codes.com/p0128

I hope this helps a bit!

P0128 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.

Symptoms: You will likely not notice any drivability problems other than the MIL illumination.

Causes: A code P0128 may mean that one or more of the following has happened:
* Low engine coolant level
* Leaking or stuck open thermostat
* Faulty cooling fan (running too much)
* Faulty coolant temperature (ECT) sensor
* Faulty intake air temperature (IAT) sensor

Possible Solutions: Past experience indicates that the most likely solution is to replace the thermostat. However here are some suggestions on troubleshooting and repairing a P0128 OBD-II code:
* Verify coolant strength & level
* Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
* Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
* Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
* If the above items check out good, replace the thermostat
* If Nissan vehicle, check for Technical Service Bulletins (TSBs), as the ECM may need to be reprogrammed to correct the P0128 code


Hope helps (remember to rate this answer).

Take note of the blurb regarding NISSAN products below

A code P0128 may mean that one or more of the following has happened:

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

Past experience indicates that the most likely solution is to replace the thermostat. However here are some suggestions on troubleshooting and repairing a P0128 OBD-II code:

• Verify coolant strength & level
• Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
• Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
• Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
• If the above items check out good, replace the thermostat
• If Nissan vehicle, check for Technical Service Bulletins (TSBs), as the ECM may need to be reprogrammed to correct the P0128 code

DTC P0128 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

What does that mean?
This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.

Symptoms:
You will likely not notice any drivability problems other than the MIL illumination.

Causes:
A code P0128 may mean that one or more of the following has happened:
* Low engine coolant level
* Leaking or stuck open thermostat
* Faulty cooling fan (running too much)
* Faulty coolant temperature (ECT) sensor
* Faulty intake air temperature (IAT) sensor

Possible Solutions:
Past experience indicates that the most likely solution is to replace the thermostat. However here are some suggestions on troubleshooting and repairing a P0128 OBD-II code:
* Verify coolant strength & level
* Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
* Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
* Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
* If the above items check out good, replace the thermostat
* If Nissan vehicle, check for a TSB such as this one. The ECM may need to be reprogrammed to correct the P0128 code


Hope helps (remember rated this).

p0108 map curcuit high input, p0128 coolant temperature below thermstat regulating tempurature, p0341 is camshaft position sensor A-bank 1 ckt range/performance, p0401 is exhaust gas recirculation, insufficiant flow detected, p0420 is catalyst system efficiency below threshold, p1480 is manufacturer control auxilary emission controls, p1481 is same as p1480.

P0128 indicates that the car doesn't "think" it is warming up quickly enough. So either it really isn't getting warm enough, or the sensor indicating the temperature is bad. If it isn't getting warm enough the causes include a thermostat stuck open, low coolant, and a cooling fan that is running when it shouldn't be.

For a good explanation and more insight visit
http://www.obd-codes.com/p0128

Keep in mind that many cars have two coolant temp sensors. One for the computer, and one for the temp gauge. Make sure you are working with the correct one.

The P0218 Code is primarily intended to indicate a faulty thermostat.
Have the thermostat replaced

Other possible causes that could trigger this code would be:
Low engine coolant level
faulty cooling fan
faulty coolant temperature sensor
faulty intake air temperature sensor