Ok got a quick question for y'all.

I have a 2000 Cavalier 4 door. 2.2 EFI Engine

A few months ago we got a heavy snow and while I was driving the car the check engine light came on as well as the TRAC OFF light.

The check engine light has stayed on ever since and the only thing I've been able to find on the code is a OBD-II code P0480 (The PCM has determined that a malfunction exists in the control circuit for cooling fan 1)

I am under the impression that if my cooling fan was malfunctioning the car should be overheating especially since the past few weeks have had high temperatures in the middle 80's and I've been running the AC as well as sitting in bumper to bumper traffic.. I think if it were going to overheat those would be prime conditions.

Would it be wise to remove the battery cable and allow the computer to reset??

Any help would be appreciated.. I have no problems getting into wiring as I have a lot of experience with electronics.. especially vehicle electrical systems.. just haven't had the time to get into diagnosing the problem.

does the fan come on when u let the car sit and idle for a while?
does the fan come on when u turn the AC on?
whats the temp guage been showing?
u probably could try unplugging the battery for a while

I had this same thing happen to my '97 Z24 2.4 Auto. Unfortunately, it was not easy to fix. P0480 means there is a problem in the circuit from the ECM to the cooling fan relay.

This procedure has lots of steps to rule out everything in the system that can be bad, so you might want to reference a shop manual, but I'll give you a general summary here:

First thing you do is test the cooling fan itself. You can do this simply by pulling out the cooling fan relay under the hood and closing the connection between the terminals of the cooling fan itself. The proper way to do this is to actually make a fused wire between the two terminals, but all you really need to do is take a needle-nose and touch the two terminals together for a second. (disclaimer - this may cause some sparks, which are dangerous, especially considering you are right next to the battery. Also, jamming things in the terminals themselves tends to eventually break them, which is even more miserable to fix, so be gentle. Also, make sure that you do not somehow put high 12V current accidentally into the terminals that go to the ECM, you could cause damage that way too). If by closing the terminals the cooling fan starts to spin, you've ruled that out.

Then, test the relay. Apply 12V current to the pins that close the connection. If you hear a click, it is most likely good. To be sure, while the voltage is still applied, test the continuity through the other 2 pins on the relay. If you have a bad relay, you will hear no click and/or have no continuity and that's easy to deal with. If not...

Next, with the keys turned on to ACC (car doesn't necessarily have to be running), test and see if any voltage comes from the terminals going to the ECM. If voltage, you have either an intermittant wire break somewhere between the relay and the ECM or a problem in the ECM (not too fun either). If no voltage, also a wire break but more permanent.

When this problem happened to me, I brought it to my mechanic who took more than 3 hrs to diagnose and repair and he looked like he needed a few beers afterwards. This is the kind of mechanic who does most everything blindfolded and with one hand. If it takes this guy that long to do it, I can be assured it was very bad. In my case, it turned out that a wire connection somewhere in a wire loom in a very inaccessible part of the engine corroded and broke. With that being the case, I wonder what other crucial wires are next to fail on this car, which will also cost me an arm-and-a-leg to fix.

On a similar note - I'd like to know from others here, specifically those in colder climates with significant winter road salt if they are having similar wire and electrical terminal corrosion problems. I live in Minneapolis and have received 8 yrs of good service out of my Cavalier but am starting to wonder if this is the beginning of a lot of costly repairs.

I thank you both for your input.. I am going to check it out this weekend and see what I can come up with..

Have this same problem after a huge blizzard, cooling fan control circuit.

Andrew Berg wrote:
On a similar note - I'd like to know from others here, specifically those in colder climates with significant winter road salt if they are having similar wire and electrical terminal corrosion problems. I live in Minneapolis and have received 8 yrs of good service out of my Cavalier but am starting to wonder if this is the beginning of a lot of costly repairs.

I have had wires with pin-sized holes in them get corroded to the point that they show as an open in the circuit. Mainly my headlight and and a wire for my O2 heater so far. The salt hasn't been nice to my car either, I have a nice rust hole that's grown pretty big over the last 4 years, wasn't there when I bought the car. The bottoms of my doors are rusting away too!


http://www.cardomain.com/id/Gerkn

Cooling fan circuit is the code I had a couple weeks ago, ice got up there and burnt it out (fan). Weird thing was the fan still would come on, run a bit, then blow everything.
Car never overheated at all, even with collapsed hoses. In fact, I don't think ANY of the Cavi's I've owned has ever actually even gotten up near the red. Weather ranged from about 10 to up in the 40's before I fixed it.