Off Topic - Prius Burnt Harness (Great Photos!)

[Phildo]

Recently I saw a 2004 Prius sitting in a workshop yard so bought it for $500. 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 (ie www.priuschat.com).

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.

https://www.rhibusbar.com/product/nickl ... sbars.html
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:



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.
http://www.idealindustries.ca/products/ ... noalox.php



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:

[reecho]

Water ingress for sure....

[T1 Terry]

Well there ya go, I just posted a rely to your thread on the Prius Chat forum I had a harness and battery computer I could have sent to you but I think I've butchered the harness to make a battery for my pump out of the river and another pack for the "Welcome to Mannum" wall night light. I'm guessing the plug is still fine if you want to solder new wires onto it.
Does your Prius have rusty bits in the spare tyre well? If it does then there are cracks in the upper corners either side of the rear hatch hinges, I think there were photos either on this forum or the Prius Chat forum of a Prius showing the cracks.
My battery pack was corroded like that, no sign of water anywhere but it could have been humidity I guess. More likely leaking modules

T1 Terry

[Phildo]

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.

[Phildo]

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.





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

[Phildo]

I ran three charge/discharge cycles on the battery with the Prolong charger and discharger. The charger ended up showing 235v, so from that I’m assuming that all the modules are reasonably healthy.

I didn’t do anything to compare all the modules with each other - although I’ve got some balance chargers I don’t have any cables (this was a few days ago, and I’ve since found one set of cables).

The previous owner replaced two modules, but I’m assuming that they’re just random ones and not matched to the rest of the pack (ie matching Ah).

This means that the pack will possibly go out of balance in a matter of months but it will do for now. Once I’ve got some more equipment (ie charging cables) and a bit more experience then I’ll have the skill to rebuild this battery properly if/when it needs it.

But, for now, I just need a battery that will work for at least a few months. I’ll check it every month or so with Techstream and see how close to each other the block voltages are.

Some more photos… the bag of nickel-plated busbars - I wear rubber gloves when fitting them so that they are kept clean (I’m being paranoid and thinking of car headlight globes):



As well as the nickel-plated busbars I have bought stainless steel nuts (304 grade).





I was using a Ryobi cordless drill to put the nuts on and was careful in doing so (ie a few slow revolutions to ensure that the nut threads on to the module correctly, instead of just going straight to full speed) but one nut still didn’t go on properly.

After that the remaining nuts were put on and rotated by hand until finger tight.

I used a Snap-On Techwrench TECH1FR240 to tighten each nut to 4 ft-lb (ie 5.4Nm). The Techwrench vibrates as it approaches the preset torque figure and then beeps when it reaches it.

Tools such as digital Snap-On torque wrenches are hideously expensive to buy new, so I buy them secondhand on eBay. It will often take me months to find the right deal, but I set up searches and email notifications until I find the gadget that I’m currently looking for.

I paid $US160 for this one in mid 2017 and hadn’t used it until now. I actually bought it to use on an exotic Aprilia SXV550 motorbike that I have, but that bike and I haven’t been on speaking terms for the last couple of years (ie it took offence to the Yamaha starter motor that I fitted).

If the Aprilia is upset about the Yamaha starter motor then it’s going to be really, really pissed off if it finds out that the expensive Snap-On tool has been used on a Toyota hybrid instead.

Link - Snap-On Techwrench TECH1FR240: https://store.snapon.com/Standard-Model ... 42510.aspx

[Phildo]

Does your Prius have rusty bits in the spare tyre well? If it does then there are cracks in the upper corners either side of the rear hatch hinges, I think there were photos either on this forum or the Prius Chat forum of a Prius showing the cracks.

One car I worked on a while ago had a heap of water in it. The 12v recess was half full, and the spare wheel area had a bunch of water as well.

I now all about Prius drain plugs. Some day I'll get ambitious and see if there's some sort of one-way valve that I can use instead of the rubber plugs.



There are two drain plugs at the bottom of the 12v battery area:



When removed plenty of water drained out:



These plugs can be access from underneath the car. Needless to say, that becomes a thing to check whenever a Prius is on a hoist.

Cracks in the roof. Goody, an excuse to avoid washing the car.



Toyota designers are funny. They really need to get out more.

They might know how to design cars, but they're completely crap at figuring out the size of a western person's hand.

This makes some of the drain plugs a tad hard to access.



A quick application of a Dremel cutting tool and I was able to access the rubber plugs on the rear LH side. Those plugs now reside on the inside of the car, where they can be accessed much, much easier: