Q: Service engine light came on.

asked by on November 21, 2016

Took the car to Auto Zone it read P 0128 coolant temperature low. I watch the gauges and it is usually at the first 1/4 mark on the temp. I have had trouble with the heater not blowing warm and the temp. dial not going above 65 degrees although sometimes it will turn to 90. Service engine light went off for a few days by itself but came back on again. The thermostat is very hard to change on this model. Do you think it could be the ect sensor or the thermostat?

My car has 155000 miles.
My car has an automatic transmission.

Hello, this code represents a slow acting thermostat getting to engine operating temperature which is about 195 degrees. The computer monitors the time to get to operating temperature, if it takes too long it will set this code. The issue could be the thermostat opening to quickly to circulate engine coolant. Low coolant level would also give this concern, that would mean the system has a leak. This would cause a cool operating and less heat to passenger compartment. The control panel for temperature would be a different concern. If you’d like, a certified Your Mechanic Technician can come to your location and inspect this condition. Please look at this web site for more information and service options. thermostat/low heat

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Ths car stalls sporadically when the engine warms up - 2000 Toyota Echo

I wish you had told me which red light illuminates. I am going to take a shot at it and guess its the battery light. You may have an alternator related problem. It could be a loose belt, the alternator...

Service tire monitor warning, tire pressure a bit high

This is likely due to the fact that the person who changed your tires may have broken your TPMS sensor in that particular wheel. If the pressure sensor is not giving a signal at all, this would mean that the...

My car wouldn't start after battery was just replaced my car cd player is running after I turn the car off

Your CD player definitely should not be running after the key is off and out of the car. It will certainly drain your battery. So the good news is you can be reasonably certain about what is killing your battery....

Related articles

How Long Should It Take a Heater to Warm Up in Cold Weather
When When you turn on your car’s heater, it should start blowing warm air. If the engine is already at operating temperature, this should happen immediately. However, if your engine is cold, it will take longer and if the weather...
How Long Should It Take a Heater to Warm Up in Cold Weather
When When you turn on your car’s heater, it should start blowing warm air. If the engine is already at operating temperature, this should happen immediately. However, if your engine is cold, it will take longer and if the weather...
Symptoms of a Bad or Failing Heater Control Valve
Common signs include the heater not working, coolant leaking from under the engine, and no voltage across the heater control valve.