legacycentral bbs

I have a '94 Legacy wagon, auto, w/ 220+K on it. I had been getting intermittent CEL, codes 21, 32, 35. I replaced the canister purge solenoid, cleared the codes, and now I'm just getting an intermittent 21. The CEL light comes on for about 10-20 seconds while the temp gauge is in mid-travel between cold and operating temp, then goes out and stays out. Temp gauge on the dash appears to be functioning normally. Does this sound like a "typical" sensor failure or might there be something else at work here? Anything I should be aware of if I need to replace this?

Thanks.

The gauge on the dash and the ECU use two different temp sensors.

How does the car run when cold?

The sensors are pretty cheap, around $20, so I'd suggest replacing it.

The car runs fine when cold. If I just let it sit and warm up for awhile (I usually don't, but lately I have while I scrape the windows, I live in northern MN) idle speed fluctuates a bit, sometimes jumping to 2,000 RPM).

I just replaced the coolant temp sensor on mine, also. I was surprised to discover that a 3/4" deep socket fit even more snugly on the sensor than any metric size. Also I had to temporarily disconnect the PCV hose so I could get at the sensor at the proper angle. Easy job, though.

Thanks for the reply, I just picked one up. Did you have to drain any coolant, or did you lose much when you pulled the old one?

I just plugged the hole with my finger as I pulled the old one out and put the new one in. Probably only lost 5 drops of coolant. It's completely unneccesary to actually drain any coolant out, as the manuals usually say to do. And make sure the socket you use is a deep one, so it can fit over the electrical connector. And a 6" or 8" extension helps a lot. But, seriously, I changed mine in 5 minutes while on a cigarette break at work. Easy peasy lemon squeezy.

Thanks, good to know since I don't have a garage and it just warmed up to -1. Was yours doing the same? Intermittent Check Engine Light during warm up, error code 21?

Actually I was having a totally different problem, but I initially thought the coolant temp sensor was the culprit, so I changed it. It turned out to be something else, but I'm glad I changed the sensor anyway because when I took mine out, it fell apart in my hand; the plastic part where the electrical connector connects to it just fell off of the metal part. It was really corroded, but it never did throw a CEL. But changing it fixed a couple of little electrical quirks I was questioning previously, so it helped there too.