Noticed my 3.8L engine (2002 Chy Town/Country mini Van) , cooling fans (2 fans on this model) were running uncommanded or sporadically, even after the car has been setting for several hours (overnight) and cooled down. The battery, of course, became drained. Has only happened twice in the past 30 days or so. Likely will happen again. Any suggestions on a diagnosis?? thanks.
XDGT03
07-01-2007, 06:27 PM
faulty coolant sensor
faulty PCM
there is also a sensor/relay on the a/c that triggers the fans and that could be bad as well. I can't remember the name of that one.
Now you say they are coming on when the vehicle is off? I think that means it is probably the PCM or some grounding issue. Take it to Auto Zone and have then hook up the OBDII reader and see if there is anything in there. Even if your CEL is not on it could still be storing a code.
eagle claw
11-18-2007, 02:44 PM
thanks. I had a local dealer run the diagnostic and PCM code was P1491, Radiator cooling fan relay. They did a remove and replace on the relay. This was in early Jul 07. Just noticed today, "engine light" is back on and ran by AutoZone, and PCM code P1491 again.
Any thoughts?
Also, is there a clean way to clear PCM codes?
gas28man
11-30-2007, 11:57 AM
I'm sort of surprised to see the cooling fan relay issue return. These things are a known problem area, but to have a new one go bad in just 4 months is highly unusual. Gotta be something making them go bad. Perhaps a bad motor on one of the cooling fans is drawing too much power, cooking the relay. The fix would be replacing the cooling fans and the relay.
And you clear your codes by pulling the negative battery terminal for about five minutes.
