QuestionMY CHECK ENGINE LIGHT KEEPS GOING ON&OFF. HAD
THE CODES CHECKED TWICE AND WAS TOLD THAT
THE COOLANT TEMPERATURE WAS TOO HIGH.COOLANT TEMP
GAUGE ON DASH SHOWS NORMAL OPERATING TEMP.HAD THE
RADIATOR FINS CLEANED AND THAT MADE NO DIFFERENCE.I HAVE ALSO NOTICED THAT AFTER SHORT
(4MI) EVENING DRIVE BOTH COOLING FANS WERE ON.
COULD THE COOLANT SENSOR BE DEFECTIVE AND WHERE
IS IT.
THANK YOU FOR YOUR ANSWER
AnswerThe code with description "coolant temp high" will set for any coolant temperature outside what the computer considers a normal range. If your lamp is back on, someone with a scan tool can look at the freeze frame data (data at the time of the code setting) and see what the coolant temperature reading was at this time. Typically, I see a reading of -40 degrees when this code sets (if the vehicle isn't actually overheating). This temperature indicates an open circuit in the coolant temperature sensor circuit. The computer will then turn on the cooling fans because it cannot tell how hot the coolant is-- it's decided the readings from the sensor are not accurate.
I'd recommend replacing the coolant temperature sensor and making sure the connector has good electrical contact with the sensor terminals. You'll find it screwed into a coolant passage under the ignition coil.
