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A/C stops working, Service Engine Soon: Safe to drive?

Hi Car Talk Community,

Here’s my situation:

I was driving back from a conference last Sunday afternoon with 4 passengers in 85 degree weather.

After about 5 minutes on the road, I noticed that the A/C stopped working and the vent wouldn’t increase in speed under any fan setting. 30 minutes later, I hit stop-and-go traffic (with more stop than go) and the Service Engine Soon light came on. The engine was laboring just as we got out of the gridlock. The last 7 miles were smooth and at 45mph.

After the car cooled, I checked the oil and engine coolant–both were fine. The fan worked again as well, now responding to each fan setting. And the Service light went off.

And this is where my knowledge of cars abruptly stops–if it’s not the oil or coolant, what is it? More importantly, is it safe to drive 150 miles on Friday to get to my home dealership?

I’d appreciate any advice or ideas.



What year is your Buick? How many miles? What’s the state of maintenance like? Do you always follow the schedule in the manual?

When the service engine light comes on it means that there is an error code stored in the computer. The best way to get a start on the problem is to find out what the code(s) was/were. If it is a '96 or later many auto parts stores will read the codes for free. If the light is not on you’ll need a scanner that reads “history” codes (ones that were set but that the computer cleared). You can call around to the auto parts stores and ask about that. Other than that, if the light comes back on any code reader will pull the codes.

If you get them, write down the exact code - they look like “P1234.” Don’t bother with whatever description someone might give you. Just get the codes and post them in exact form.

You also don’t need a dealer. Most any decent independent mechanic can deal with and probably for less without trying to oversell you on things.