Need help reading DTCs due to A/C failure.

My Prius is a '05 with 275K on the clock. The wife was driving it to work the other morning and the A/C stopped working, boy was she pissed. Anyways, after previewing some of the threads on how to fix a broken A/C, I stumbled upon a thread that said the inverter pump might be bad and thus force shutting down the A/C compressor in order to keep the Inverter alive until repairs can be done. So this morning I replaced the Inverter pump and started the Prius up to see if this fixed the no A/C problem. While running the engine I did notice a weird sound coming from the passenger side of the engine bay. It wasn't a grinding noise but similar, kinda a brrrrrrrr noise. This got me thinking about if my A/C compressor is dead.

So I tripped on over to PriusChat and begin reviewing threads about Compressor failure and one fellow posted something that piqued my interest. He stated that DTCs could be retrieved by pressing a couple of buttons on the steering wheel and then press the start button a couple of time and the DTCs will appear on the MFD.

Thus, now I come to the smart guys on this forum who have the knowledge of the Prius Gods and am humbly asking for your assistance. Could you tell me what DTC 21, 42, and 76 mean?

Thanks.

 

One more question.....Where is the compressor located? I've looked and haven't figured out if it's at the top of the engine, towards the rear, on the bottom or in the back of the trunk. This is like trying to find Waldo.

 

I wanted to give a follow up just in case someone in the future who has a similar problem might get to the bottom of the problem and solve it. I read a thread about looking at the radiator fans and see if they are working. Well, since I feel like I'm a three year old at times, I didn't know how to figure out how to make the fans come on. So I said, screw it, I'll just do what the author instructed....change out the relays to the fans. So I pulled the relays in the fuse box under the engine hood labeled Fan#2 and Fan#3. Took them down to O'reillys and asked if they had any in stock. The clerk found the five prong relay with no problem for eight bucks and after a long search he located the other fuse, it was only twelve bucks. Ugh, thirty dollars for two fan relays, Oh Well that's the cost of keeping momma happy. I plugged in both relays and turned on the A/C and it started blowing cold air. It was very nice not to have to pull the compressor and evacuate the freon lines along with the service cost to refill the lines with the correct amount of freon.

This isn't a hard fix, but it took a lot of head scratching to figure out what might have been the problem. I don't understand the reasoning behind the engineering that turns off the A/C when the fans don't turn. But that's why I'm not an engineer. I'm so glad I didn't have to replace the fans or the compressor, but I did probably replace an inverter coolant pump that might not have been needed to be replaced.

Hope this might help someone.

 

I don't know. When the A/C stopped working I can only suppose the fans stopped turning because the relay was bad. I was not in the Prius when the A/C died. I did try twice to see if the "brrrrrrrrr" noise coming out of the compressor was the culprit. It never cooled the cabin, thus I figured the compressor was dead. I did not notice, at that time, if the fans were turning, it just never occured to me to check them, plus they would not have spun anyways with a bad relay. In a normal car the fans would turn even if the compressor was dead. But the Prius engineers made the decision to have the compressor not run while the fan motor relays were not working properly. I was working off the assumption that the fans were good and were turning, but I did not check to see if that was so. Assumptions can bite you, sometimes.

If I had known about the bad relays first my frustration level would have been low. But I had to sit in front of my computer for a few days to surf the web and try to find what might have been the culprit. So, I did the shotgun approach and on the second try I got very lucky. I was too focused on finding the cure instead of finding a flowchart on which steps to take first to find the actual problem. So now the wife is happy that she can drive a gasoline sipping whip instead of a gass guzzler. Happy wife, happy life. I'm not saying I'm the greatest Prius whisperer that has ever tinkered on a Prius, but instead, I'm one of the lucky guys who only had to tempt the Prius gods twice before they responded with a bit of good fortune.