Based on the symptoms you've described I think that's a good bet. You're turning high RPM but you're not making power, in fact you're spinning the engine beyond the torque & horsepower peaks. Hopefully you can find some good used and a wrench (mechanic) you can trust.

 

Another thing to note about cats: please fix whatever caused them to get clogged/broken. I've changed a few without doing that and it's always led to it failing again.

 

Another update lol. I used Forscan and checked the oxygen sensors before and after the cat and they were within range of what it was supposed to be. It looks like the cat is good, not positive, but pretty sure, especially since the Cat emission still clears easily.

So I started over again, this time i ran every sensor i could fit on the screen and noticed the Hybrid Battery was still getting hot even after i replaced the fans. The fans are working, but the battery isn't cooling off. I found the coolant lines running to the battery and one was ice cold and the other really warm, it was 110 degrees out today. So it looks like my air conditioning for the battery may not be working, but I'm not sure how to figure it out. I will do some research. but if anybody can give me some advice it would be appreciated.

 

Check the TXV for the rear A/C. The top of it should be cold. If it's not opening up then refrigerant doesn't pass through to the evaporator and a/c doesn't work. There is also some kind of 2 way switch that sends A/C to the rear but if it fails I think it would set a code. TXV is pure analog and very cheap. The problem comes from having to replace all the refrigerant when changing it and sucking down the system. If the evaporator is warm and the TXV isn't cold, there's your issue.

 

I'm starting to think the problem is the temperature sensor in the battery. I took the panels off the back and verified that everything seems to be working. The temperature at the rear condenser was 60 degrees F. The plastic leading to the battery intake was very cold, and both fans are working, but the battery temp was 90 degrees F and it didn't drop. I lifted the carpet and the battery was not warm to the touch.

Does the computer use the battery temperature to decide how much juice it can use? Because the higher the battery temperature goes it seems to match perfectly how much power I have. When its around 90, I push the gas and it goes, when its 105, i push the gas and it just redlines the RPMs but doesn't accelerate much. Unless anybody has a better idea I will figure out where the temperature sensor is and see about replacing it, at the minimum I guess I am going to have to open the battery up and see if somehow there is a blockage in there. Maybe one of those leaves I found when I replaced the fans got further into the battery.

 

Now that i think of it i do have another question. Is it possible for the blend door actuator to open and close the door to the outside air but still leave the other door closed? If so, that could explain why the duct is cold but its not really getting to the battery. It may not be possible, but if it is, how would i check?

 

If it's operating and the fan is blowing you can see what kind of air comes out.

 

Took it apart and i guess the actuator has been changed before. When they put it back together the little arm that closes the open air part was put on backwards. It looks like both doors were always closed at the same time and not letting any circulation through. My battery temperature has dropped a lot, it was staying around 81 degrees F yesterday. Unfortunately there wasn't a dramatic change, only a little one. I will drive it a lot over the next few days and see if there is any change. The problem sounds like the thread where the battery overheated and stopped working like it used to. I'm going to have it checked out to see if maybe the battery just can't push becasue of staying hot for so long.

 

Oh man, ugh. Just UGH! and "bang on the steering wheel" anger. I'm sorry to hear this, it's such a bummer to hear about incompetent repair that causes big problems later down the line - and it's not immediately obvious, at a glance. I once had an online friend from Britain, really smart guy, whose specialty was knowing *everything* about the original "UR" Audi Quattro Coupes (turbocharged, AWD, very special cars, limited production, basically hand-built and more esoteric than humanly possible, except for German engineers) who had seen more slipshod and incompetent repair than most people can handle and then tried to fix them back up, so they ran like they should, an almost impossible task. FTM says the actuators were in and out of his shop repeatedly over six generations (suffix A through F for #4$#ed, I guess.) It sounds like some "monkeylad" (which is what my British Audi friend called most repair techs who didn't know/care about what they were doing) screwed yours up.

At least you found it and identified the cause, which is better than nothing. Let us know how it goes after driving it for a while. On a cool day, rebalance the battery with FORScan if you can and keep us apprised. That takes about 20 minutes, I would do it in the morning around 70 degrees if you can, out of direct sun. Fingers crossed for you, I don't even have this system on my car so my HV battery is totally at the mercy of my interior cabin temperature. Best wishes and thanks for letting us know the news.

 

How hot does it have to get before the A/C comes on. I've never checked on my rear one and I don't feel it turning on the compressor ever. Visually it all looked "new" when I had the back panels off. Only drove around in at most 95F. I don't see anything happening to the battery so just wondering.

Before I made the A/C work I did have a couple of times where the battery fan came on when I pulled over so I can definitely hear those when they come on. I leave my econ switch on and still too cheap to use A/C for the cabin. Only once ever did it refuse to go into EV before I made sure any cooling worked.

I wonder if there is a way to force it to cool the battery from the scan tool.