2004 Chrysler PT Cruiser • 4 cylinder FWD Automatic • 1,038,956 miles

Check engine light came on Auto zone ran their little machine it says engine running cold he said one of two things not the right amount of coolant or thermostate is not working right. Checked coolant so does that mean I need to replace the thermostat.
November 22, 2010.

It cold be a few other things. Have you paid attention to the temp gauge in the vehicle? If so, does it run at a normal operating temp?

Normally that code does not result in turning on the Check Engine light. If you live in a cold winter climate, every Chrysler product will set that code this time of year when the engine doesn't reach full operating temperature within six minutes. The code will erase automatically when the weather gets warmer in the spring, after the problem doesn't show up during 50 consecutive engine starts, (about two weeks).

If your thermostat is defective, you will not get hot air from the heater and the temperature gauge will read lower than normal. Most auto parts stores use inexpensive code readers. Your mechanic uses a scanner that can display live sensor data. An out-of-specs coolant temperature sensor, (which Chrysler has almost no trouble with), can cause that code to be set. There are two coolant temperature sensors. One is for the gauge on the dash and one is for the Engine Computer. That means the gauge can read normally while the computer thinks the engine is cold too long.


Nov 22, 2010.