Prius code p3000 fan blowing hard

what are you reading the code with?

how many miles on her?

 

ah, thank you. first, you should get toyotas official reader, tech stream. which will give you the details needed to make proper repairs.
second, replacing cells and rebalancing is a very complicated and time consuming affair. did you follow detailed expert recommendations?

 

all the best!

 

Welcome back.

Did you test the replacement module(s) and confirm they were a good match to the other modules in the pack? If the answer is "no," then you can't say it was done right. It may be close to right, but you clearly are back to some sort of battery issue. Additionally, there is nothing preventing one of the 168 cells in the pack from imploding.

Check back in when you've done the MiniVCI health check and logged some data on the HV battery.

 

One more thing... I don't remember in the original thread, but did you thoroughly clean your bus bars and sensing wires?

A user recently tested and reconditioned their battery with an HA unit and even tested module capacity - replacing two bad ones. For a week, things were great... then code with a "block becomes weak" error. That block had IR in the 30s vs. the low 20s of the others. Upon inspection, his bus bars were horribly corroded on the terminal side, and he didn't notice it the first time around. Cleaned bus bars, and he's good.

Incorrect torque on the nuts could have a similar effect. 48 in-lb.

Techstream will likely get you pointed in the right direction.

 

Given that the hybrid fan is on, it is unlikely that you have only a p3000 code.
Likely that there is another code that you are not seeing.
Once you have correct tools you will be able to see additional data (like vblock voltages, etc)

 

what is the cause for that corrosion? would applying of dielectric grease help prevent that?

 

The copper corrodes at the positive terminal. I don't have the full explanation for it.

He was in a coastal area. Salt laden air makes it much worse.

Even here in AZ, we get corrosion, but it's dramatically reduced, and it's only present on the terminal side of the bus bars.

Dielectric grease is primarily intended to seal connectors and is not recommended for use on the contacts themselves. I would be very wary of putting dielectric grease on the bus bars. 120A is a lot to push through an insulating film. I would hope proper nut torque would take care of it, but I would rather deal with the corrosion.

The corrosion generally occurs OUTSIDE the contact area between the terminal and bus bar. It's generally not an issue until removed and re-installed w/out cleaning.

 

actually it works great directly on the contacts. i fixed quite a few intermittent connection problems in cars, PCs and laptops by applying grease to the contacts. i don't understand how it works (contraintuitive), but it does.

 

It works by contact pressure scraping removing or thinning the grease to permit conductivity.

Fixing a low current connection is one thing. Fixing a 100A connection is another. I just don't see that the benefits outweigh the risks.

Steve

 

Maybe there is higher contact pressure while the contacts are covered by grease?

Either way, people who used it had great results and people who didn't use it swear against. But it shouldn't be used when sparking, due to silicon carbide fouling the contacts.

Alternatively, one can clean the contacts, assembly them and cover the metal from outside only to seal from air.

 

What was the output of the health check?

When you see the list of ECU's available, double click HV Battery.

 

^^^ +1 to what S Keith said.

Any DTC's should be on the screen after the health check completes.

Did you get any DTCs? If so report them here.

 

Its corrosion from the battery gases. And the bus bars are almost 100% copper and easily corrode but the terminals are not 100% copper (too soft) so there's dissimilar metals there and a perfect storm of galvanic action and corrosive gases. Make sure you use new nuts too.

Dielectric grease is a poor product to use there. It has no anti corrosion effects. Mainly just used to keep moisture out of electrical connections. Use an anti corrosion product like Nolox on the battery threads and a thin coating on both sides of the bar. The battery side of the bar see's the most corrosion as its exposed to the most battery gas.

Use Nolox especially if you have cleaned off all the corrosion and exposed fresh shiny copper surface without the manufacturer patina. That surface will instantly corrode without an anti corrosion product applied.