Codes P3000 and P3009 on 2002 Prius

[beth524]

I need some help here! I have had the exclamation point warning light and car icon with exclamation point coming on and then going off for a couple of months now (seems like it happens when the car sits in the driveway in hot sun). I finally got it in to the dealer when the lights were actually on, but by the time they looked at it, they were off. They checked the code history and found P3000 (HV battery malfunction) and P3009 (leak detection). They said without the lights on there was little they could do and stated "Tested as oer manufacturer instructions, no problem found at this time". They advised me to come back when the lights were on again.
I have replaced the 12 volt battery, the engine ECU (under warranty), had the sealing of the battery done years ago, and changed the transaxle fluid (looked fine and clear). The car has 65000 miles and has not been showing any symptoms--drives as it always has. Should I be worried?

[tochatihu]

There are subcodes for both 3000 and 3009 but I am not sure we could do much with that additional info.

There is basically nothing that an owner can do to help out the HV battery other than making sure that its ventailation system is functioning OK. Pull out the orange service plug and re-insert it? They probably already did that.

If I told you not to worry, would it matter? That your car appears to function OK is good news. Let's hope it continues to do so.

[Patrick Wong]

Hi Beth,

Next time the warning lights appear, head directly to your Toyota dealer and leave the car READY. Have the service advisor see that the warning lights are on and have the tech retrieve the DTC before the car is turned off.

Then, you'll probably get a new traction battery (or at least a new traction battery ECU) under the hybrid system warranty.

[beth524]

Hopefully that will work--I complained and spoke to the service manager who said that next time they come on I will not have to wait days for an appointment (when invariably the lights will have shut off). I was worried about driving with a "high voltage leak". He also told me that this is the second time these codes were retreived and is going to speak to Toyota to see about getting a replacement battery. Hope so-- my warranty expires soon!

[Patrick Wong]

DTC P3009 means that the battery ECU has detected a high voltage leak to ground. Normally both the positive and negative sides of the traction battery are isolated from ground.

The leak could be caused by any component in the following path: traction battery, traction battery ECU, battery cables connecting the traction battery to the inverter, inverter, or transaxle.

The traction battery might be the cause of P3009 if a battery module has an electrolyte leak that touches the battery case. This allows battery voltage to flow along the electrolyte and leak to the battery case, which is connected to the body and hence the electrical ground.

[beth524]

I went back to the dealer while the lights were on yesterday. They again got the codes 3001 and 3009 and then cleared them. The first time I started the car today the warning lights were back on. Does this definitely point to a battery issue or could it be the transaxle, and should they be doing something more than just reading the codes and then clearing them?(which is what he did yesterday). I thought I understood that more diagnosis could be done if the lights remained on. (more than just checking the codes)

[Patrick Wong]

Now that the DTC have been confirmed, I would expect the Prius tech to do something to actually resolve the problem. Suggest that you ask when this will happen.

For example, there are procedures that will allow the tech to determine where the high voltage leak is coming from (the P3009 issue.) Once it is known what part is causing the leak, then you will know what has to be replaced.

[beth524]

So, the saga continues. I was in again after the service manager told me to come in for more testing. No warning lights on this time (but as I said, the 3009 code was found 3 times). I was told they could not find anything wrong with the car and to keep driving until I had a problem. What procedures should they be doing to find the HV leak? And is it possible to get these codes and actually have NOTHING wrong with the car? I just want to be sure if it is the HV battery that I get it covered under warranty. As I mentioned I do not trust this dealer, but at least I haven't had to pay for the last two of these "diagnoses." Thanks!

[Patrick Wong]

Hi Beth,

The Toyota repair manual explains how to diagnose the failed component when P3009 is logged. Here's an example of what an independent Prius specialist did to troubleshoot the problem: Prius: 1st gen - Replacing Transaxle

Can you find another dealer in your area who has competent Prius repair techs on staff?

[tochatihu]

"Can you find another dealer in your area who has competent Prius repair techs on staff?"

Yes. please make every effort to do this.