Posted: Wed Apr 10, 2013 9:57 pm Post subject: What's the cause???
I have a 2001 Impala 3800. A while back toward the end of summer I noticed that when i shut the car off the cooling fan would stay on for about 5 minute. I then noticed that my temperature gauge would sporadically not work in conjunction with the cooling fans. If the gauge works the fans shut off. I then noticed that when the gauge didn't work then the air conditioning didn't work. So if the the gauge was working all was fine but if not the fans stay on and no air conditioning. A couple months ago the gauge the gauge quit working all together so no air. No other problems. Car never over heated or anything. Now that summer is here I need to get it fixed so I have air.
Anyone know what can cause all this?
Thanks for any info. Jared
If the sensor fails, the PCM doesnt know the exact temp, so it disables the AC to help protect the engine from overheating. It will also make the fan run after the car is off just in case its running hot.
The PCM acts as if its running hot as a fail safe because it just doesnt know the real temp.
If your ECM doesn't know for sure what temp your car is at, it goes into a protective mode and runs the fans all the time. Hard to say what caused it in your case, but I would start by replacing your thermostat. Then replace the coolant temp sensor located just under the thermostat housing. Both are cheap and easy to replace.
Check the harness first - it runs right above the exhaust crossover and the insulation can melt off the wires and cause them to short together, causing a P0128 code due to the PCM not getting the input from the sensor.
_________________ 2001 Galaxy Silver 9C1 w/ L67 and 4T65E-HD...and a few other mods.
I had this same problem a few years ago and it was the coolant temp sensor... But when I changed it the fans continued to run all the time... I had to disconnect the battery to reset the computer (or something) before it started working correctly again...
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