2002 Gen 1 Prius - P3009, P3006, P0420 and decelerating

I have a 2002 and stay far, far, far, far away from the dealers because things just get out of hand. I would go to an independent shop or authorized hybrid shop to get a realistic diagnosis. There are lots of salvage parts out there that could be obtained to cobble your vehicle back together once you know what’s really going on. In my opinion, dealers simply scare you into big repairs so much, that you’ll step up into a newer vehicle. It can all be so overwhelming. For the amount you quoted , for repairs you could be investing in a 2005-2008 model for a few more thousand dollars with about 50K miles give or take, which will give you so much more life in your car.

 

By the way, I just fixed my P0420 problem after years of skirting emissions by replacing the spark plug coils. There are 4 of them, one recently started throwing backfire errors and I found a second one that was not throwing errors but when I replaced it no more P0420. Put it back in the car, P0420 comes back quickly.....

So it might not be the cat, and these are consumables when you get into the 200k mile range.

 

For the pack yes it's replace time. I did mine at 150k with a set of used Gen II cells for $1,000 swapped into my battery and it's been fine ever since (210k miles now). But trying to swap cells doesn't work, you fix one block and another one blows.

 

My 2002 Prius was starting to throw a P3006 code off and on for a while (and i was getting low power like sean CO1 every now and then). Finally had a good mobile mechanic come out and swap out the one bad cell with a good one and put in a similar cell on the other side of the battery to even it out. That was about 7 months ago, no problem with it so far, if another block blows I'll let you know.

 

If you are capable of doing any work yourself, your costs would be a lot cheaper. It only takes a 2-4 hours and no special tools or expertise to swap batteries. Unless SC is anal about their vehicle inspections, you can replace at cat with an aftermarket unit for $200-$300. If you need a stock unit, I have one in my parts car I'll sell for $500. From my understanding, the 3009 isn't necessarily a leak in the HV battery, and doesn't refer to a cell leaking acid. You just have a wire grounded somewhere. The most likely spot is the wiring harness in the battery and, again, it requires no special anything to replace it for $130.

 

This is true and not true at the same time. It is true that a P3009 is not necessarily in the HV battery. But if it is, it is highly likely (especially in a Gen 1) that the cause is electrolyte leaking from one or more modules. However, it is not a dead certainty, so yes, it could be a grounding problem in a harness. That is why we check all this in the diagnostic tree.

If you were replying to David Botan, who has jumped on this thread, his code is P3006, which according to the first post is P3006 battery levels inconsistent (block 1 bad). I can't find this code myself.

 

Wouldn't a broken sensor wire on the battery harness cause a 3009? And those aren't necessarily caused by leakage, right? I was getting a 3009 and found a good video among the archives here that states the cause can either be in the battery, inverter, or transmission, and details a diagnosis process. To wit, IIRC, you first clear the code. Then, just turn the key on, but don't try to start. That limits the electrical current to the battery. Wait a couple of minutes. If the code doesn't reset (CEL/triangle), the ground isn't in the battery. Next, start the engine, but quickly shift to Neutral. That stops the electricity from going to the transmission. Again, wait a couple of minutes. If the code resets, the ground is in the inverter. If not, put the car in gear, so the electricity goes to the transmission and see if that's the source.

It worked on mine. Soon as I started the car and put it in Neutral, the code set. When I shifted to Park to get out and look at it, the CEL/Triangle went out. Did it a couple more times with same result. Got out and looked at my inverter and found one of the connectors was lose. Pushed it closed and my light went out.

Bad news: after about a week, my light came back, and like before, my reader isn't pulling any codes (I paid a shop with Techstream $20 to read the 3009 last time). Not sure if I have another 3009 or some other issue.

 

No, not that I'm aware, that will set a different code, codes something like P0Axx, e. g. P0ABF, P0ACx, P0AFA, etc.

A P3009/P0AA6 is always a ground fault leak. They are not necessarily in the HV battery, as the rudimentary test you describe also indicates.

If it is in the HV battery, it almost certain that the cause is leaking electrolyte. It is unfortunate that the word leak is used here in two different contexts and that seems to be leading to the confusion.

 

Yeah, I was confused by it as well.

 

Take the HV battery apart and clean the terminals. Get those connections shinning. Your other problems may go away. Again, I would addres the HV battery first.

 

Update: Swapped in a harness from my spare battery and now it runs great! Buyer supposed to pick it up Friday.