Firstly, I apologize for posting a mazda issue to a Toyota thread, but the fact is that over the past three years that I have been frequenting this group, I have grown to trust the replies (diagnostic/advisory) of the members that frequent this group, and I could not find a mazda group in alt.autos.
Car in question is my friend's 1998 Mazda 626, 6 cyl, 65 k mi. CEL came on last week and has been on intermittently for the past week. It came back on tuesday morning and has been on since then. He took the car over to Pepboys, where they retrieved the P0117 code (ECT input voltage low).
Other symptoms : AC does no blow cold air after the car has warmed up!!! (its 91 degrees in NJ). Its almost as if the ac compressor clutch disengages once its attained normal opertaing temperature. The coolant temperature gauge stays at half scale while the car is idling but shoots to the Hot mark while driving. If you turn the fan on to high speed and the cabin temperature selector to HOT, the coolant temperature drops to 3/4ths hot scale. Pepboys wanted USD 90/- to run the engine diagnostics. They think it may be the ECT sensor/ thermostat/ AC refrigrant too low ??. I had him buy a haynes manual, which demonstrates the procedure to check and replace ECT, which we are going to do today. My question is what other things to look at/consider if the sensor check comes up blank..ie is the ECT sensor is ok.
Appreciate your feedback.