Photos - P3030 - Burnt Wiring Harness

Recently I saw a 2004 Prius sitting in a workshop yard so bought it cheaply. Rather than spend money on a tow truck I tried to get the car to move under its own power but was unsuccessful.

I'll get this battery working in a couple of weeks but here are some photos you might find interesting/amusing.

Error codes:
P3000 - Battery Control System
P3030 - Disconnection between battery and ECU
C1259 - HV System Regenerative Malfunction
C1310 - HV System Malfunction
B1423 - Open in Pressure Sensor Circuit/ Abnormal Refigerant Pressure (Need to check the sight glass for bubbles)

The P3000, C1259 and C1310 are fairly generic hybrid battery errors that don't point to anything specific.

I hadn't seen the P3030 before, so did some homework on that one (thank you PriusChat!!!).

I saw some photos and information to indicate that there was a fault between a wiring harness and the battery ECU.

Having confirmed that I wasn't going to get the Prius moving with that error I removed the hybrid battery and took it home to tinker with.

Sure enough, where the side wiring harness plugs into the ECU has burnt out.

There is also a lot of corrosion on the copper busbars and nuts. I'll be replacing the busbars with nickel-plated ones that will arrive from China this week (ie the nickel plating prevents the corrosion).

For nuts, I've got some 304 stainless steel ones.

Toyota should have done both of these things when they built these cars.

Nickle Plated Copper Hybrid Battery Bus Bars
I paid $US75 + $US50 freight (ie $US125 total) for 220 bus bars (ie enough to do 8 Prius batteries with a few spares just in case).

Anyone with a Toyota hybrid should get Techstream and a suitable cable (ie Mini-VCI cable or a VCX cable). Very useful.



The Prius hybrid battery on the desk. You can already see plenty of corrosion on the copper busbars.



As expected, there was significant burn damage where the harness connects to the battery ECU (ie the lower orange plug):



The wires going into the white plug are from the temperature sensors. I’m hoping that I won’t have to replace those wires and sensors (ie cosmetic smoke damage only).







This marking on the casing is interesting - I'm guessing that electrolyte has previously leaked from a module there.



Lots of corrosion on the copper busbars - this creates additional resistance. Hence I'll be using nickel-plated busbars and stainless steel nuts to prevent this in future.



There's also corrosion on that lower black cable. There's a product called Noalox that's sold in the US that is apparently the stuff to apply to prevent this, but it's not available in Australia.
Ideal Industries - Noalox® Anti-Oxidant Compound



The orange plug is where the harness connects to the ECU.





Having learned about the theory of the P3030 code last week I went and saw someone who's got a bunch of various hybrid batteries. I got a replacement harness and ECU from the stockpile of batteries.



Stainless steel nuts:

 

The car is still sitting in the yard of the workshop that owned it.

It's going to cost me at least $100 to tow it anywhere, so instead I'm going to get a battery working so that I can drive the car.

The whole car is in rough condition. It's got 540,000km on the odometer (ie around 335,000 miles). This thing has been very, very well used.

The interior is dirty and looks terrible. I'll remove the seats and carpet and clean it all once I get the car mobile.

The paint is also faded in places. The Toyota Prius silver definitely does not like the Australian climate (ie hot summers).

It will take me a few weeks but I'll turn a worn out heap of junk into something that's useable.

 

Tonight I replaced the harness and ECU and took some photos of the old ones.

Wow.

There was quite a bit of heat in there.

I actually bought a cheap air compressor this afternoon so that I can blow dust, lint, etc, out of battery casings.















I have a set of the Hybrid Automotive Prolong charger and discharger equipment, so will charge and discharge the complete pack three times before doing some load testing on the modules.

I’ve also got a set of nickel-plated busbars and stainless nuts to replace the original parts.

If I’m lucky then all the modules will be ok and I can get away with just some basic cycling with the Prolong equipment.

 

Yes, the workshop owner said that a while ago they replaced two modules, the car ran fine for six months, then died and they left it parked out the back after that.

A photo of the top of the pack shows that modules 5 and 9 (going by their numbering system) were replaced. Module 9 is directly above the stain on the casing (ie the previous module leaked).



It's been connected to a Prolong charger for a few hours now, and is showing 234v. I'll leave it charging/balancing for the night and swap to the discharger when I wake up in the morning (ie 3:00 am here right now).



Replacing the wiring harness and the main cable (ie the black one below the voltage sensor tabs) - do you recommend replacing both the harness and main cable with brand new ones for each battery rebuild? I don't know what the pricing of those parts is here, but it will be extremely expensive.

The harness and main cable seem to be around $US100 for the pair in the US. I don't know what my local (ie Australian) price is, but it will be expensive. Things just cost more here, particularly when manufacturers such as Toyota know that they've got a captive market. I've sent an email to one dealership to get pricing, so I'll update this within 24 hours.

What would have caused that to burn out like that? Moisture? Incorrect fitting? Aside from fitting a brand new harness and cable on each battery rebuild, is there any other way this can be prevented?

What about the main/lower cable? Clean it? How/what with? Leave it as it is?



For checking and recording module serial numbers, I really, really, really want what Kiwi (ie forum member on here) has:

 

Ummmm... There are the three silver ones, the two white ones, the brown one, plus the wreck (for parts).

Oh, and my girlfriend now has the silver one that I'll be fixing up for her (she needs a car that's cheap to run).

Up to my eyeballs in Gen 2 Prius.

They seem to follow me home. Regularly.

Plus the four Camry hybrids, one of which is a taxi with 470,000km on it.

Hence the obsession with learning how to rebuild batteries.

Right now I need three Prius batteries and a Camry Hybrid battery. ASAP.

We can talk about the numerous unfinished motorbike projects some other time.

Sigh.

 

Let’s take a look at the circuit board.

I immediately found a glaring error from Toyota - the screws were conventional Philips head.

Wow.

I was expecting some strange fastener that requires a tool from a far-away factory that makes about two of them per year (and the next four years is already sold out).

Looks like Toyota’s ECU designer decided to phone it in that day and actually apply some common sense.

This board and wiring harness didn’t just decide to resign quietly.

Oh, hell no.

One hell of a tantrum there.

Kinda wish that I could do the same some days.





My nickel-plated busbars just arrived. Now I’m finally starting to get somewhere.

 

Well, much to my amazement the Australian pricing for the harness and cable isn’t a complete catastrophe after all.

My understanding is that Columbian drug lords have always been extremely envious of Toyota’s parts profit margins.

The wiring prices must have been set by a work-experience kid (ie intern), and will likely quadruple once a regular Toyota pricing person notices. RIP work-experience kid when that happens. (sarcasm)

However, Toyota do get to have the last laugh by not having stock in the whole country. Not one. Nada. Zilch.

Got to wait weeks for them to come from Japan (3 to 4 weeks).

But hey, they’ve got the ECU in stock in Sydney. Lovely.

*slow clap for Toyota*

Item: Voltage Sensor Wire Harness
Part Number: 82165-47040
Price ($A): $97.27 (ex Japan)

Item: Main Battery Cable (black cable)
Part Number: G9242-47090
Price ($A): $43.31 (ex Japan)

However, you can see Toyota starting to apply their usual sense of humour when it comes to ECU pricing:

Item: Hybrid Battery ECU
Part Number: 89890-47092
Price ($A): $883.61 (ex Sydney 1 week).