The battery fires at ECU sense connector thread

Don't throw that ECU away. Many components on it will be salvageable. It *might* even still work. But would need to check the ICs and capacitors that got the plasma blown towards them. At worst, it becomes a 'spares' ECU for motherboard level repair in the future.

Is the Gen 3 loom not available? I am assuming you want to get a Gen 3 voltage sense harness, and an ECU? It is probably possibly to jerry-rig a Gen 2 loom into a Gen 3 one. It would require some work and wouldn't be particularly neat, but it would work at a push.

 

I've been thinking about the whole ECU fires thing. We've seen it in Gen 1.5, Gen 2, now Gen 3. I agree completely it is about condensation. Maybe also 'tin whiskers' (check my profile pic!). A highly charged battery, electrolytes forming around the contacts, current slowly flowing and electrolysing the connectors, then a runaway reaction involving a short but intense plasma fire (hence the black deposits across the board, these are almost certainly metal *plasma* that solidified.

With the whole 'covid-19' situation, it is highly advisable to use the air-con on internal circulation before you park your car up, and make sure no sources of water are in the car. Park it in a garage or car-port if possible. Once a week start it with the air-con running. The best way to dry it out is to run it, air-con switched on (maybe fans at 75% speed), and heat at 'max'. Stand outside the car to avoid exhaling water. Then after 10 minutes, put the heat to 'max cold', leave it for 10 minutes. That will get rid of most water! And check it in the mornings for internal condensation.

My battery ECU short-circuit happened when I got a Nissan Leaf and parked my Prius up for 2 weeks. It had condensation on some windows... and gave a nice red triangle when I switched it on!

 

I agree that battery ECU corrosion is almost completely caused by humidity. The Prius tech's I know in Phoenix (probably the driest place in the US) never deal with ECU corrosion while all the guys out on East Coast (Virginia down to Florida) are plagued with it. The only difference is the climate.

Starting your car once a week during times of non use is good practice for all mechanical and electrical systems. Keeping the cabin clean and dry will prevent all sorts of smells and corrosion from developing.

If I lived in a humid/coastal climate I would definitely throw a couple of desiccant packets in the battery around the ECU. There's plenty of room for something like this and it wouldn't affect the operation of any SMR's or sensors. That should help suck up any moisture before it can settle in the connectors.

Amazon.com - Transparent Desiccant Packets Moisture Electronics


They also make some big 500 gram packs that are great for keeping the whole cabin dry. That might be a good option if you're not going to drive the car for several weeks.

Matt

 

316836-1 was mentioned but that's only the female metal receptacle. The orange parts have so much carbon tracing that they need to be replaced. The orange part on the harness of course comes with the easily obtainable new harness part number 82165-47040 so that's not a problem but it's the mate that needs to be desoldered from the computer we are looking for.

I've had this problem on 100% of the Toyota Priuses I've come across here we have 200 inches of rain per year and the leak above the hatch strut drips directly into the cooling fan and sprays mist all over the battery corroding all the bus bars and I think that moisture is what's causing this connector to begin carbon tracing which of course results in a small fire and if not attended to quickly after that is a parasitic drain to at least 1/3 of the cells on the passenger side which end up going to zero voltage and or if continuing to clear the code and trying to drive will result in reverse polarity and cell explosions. Don't ask me how I know.

Every single orange connector I have ever looked at was having problems. This includes eight gen2 Toyota Priuses.

This is a major design flaw having the pins too close together with 290 volts on them. Look down at the base of the pins they're even closer together down there. About the width of a sewing needle, completely ridiculous and there should be a class action lawsuit & recall!

 

searching for 12030 board connector turns up nothing. I'm really frustrated no one knows the part number of the orange connector on the ECU. Most of the time the damage on the ECU side of the connector doesn't extend onto the board itself and so if we could desolder this connector it would be the quickest easy fix to replace the connector and buy a new wiring harness. Use dielectric grease inside the connector heavy down at the base of the pins and Then spray the backside of the connector with confirmal coating instead of using dielectric grease which could attract dust and create arcing.

Let's get this figured out already. It's about time isn't it? What is this connector called? I'm sure it has a name is it something like a board riser or board to harness or what? There's a type a style somebody knows something. Heck the aftermarket red cylindrical nickel metal hydride batteries come with a new harness and the connector is not Orange. They know what kind of connector it is I wonder if they will divulge such information considering their technology is now obsolete because of the new lithium battery replacement kits available.

 

I sourced the pins to replace the corroded ones. It's TE connectivity but it looks like the plastic bodies were custom/special to toyota.
At least I was not able to find any in the TE catalogue.
316836-1 TE Connectivity AMP Connectors | Connectors, Interconnects | DigiKey

 

When you said the word pin I got excited! Same thing happened last time I saw this link in this thread. It's more like a receptacle though. I would like to find the pin that it mates with. Although I'm not sure that we can pull the pin out of the connector easily or if it's stuck in there. I found somebody with thousands of these connectors that solder onto the board and they sort of spoke like they could sell me some but they're unresponsive now.

 

The pcb pin connector will be moulded into the connecter body. It is a TE/Amp style connector but it is custom. I doubt somebody other than toyota oem would have it. If the pcb connector is corroded so is the plug. The pins on the plug needs a little tool to pop them out, like a small jewellers screw driver.

 

Hi all,
New to the forum and Prius.
Found a 01 that ran really good/everything worked and the exterior is in fantastic condition. The interior, seats, carpet had nasty stains as is someone was living in it. Had the carpets and seats cleaned (more like soaked) and it stayed damp inside for a long time. The car was parked for weeks so I hung 3 damp rids to try and reduce the moisture.
Started it up and drove it about a mile and all the dash warning lights came on. Towed it home and have been searching this forum for possible causes and debating on getting the Dr. Prius app.
Today I decided to remove the HV battery and found all the bussbars heavy corroded and the electrical connector to the HV module burnt at the connection. From what I've been reading that this could be caused by excessive moisture inside the vehicle. Combined with wet carpets/seats, heavy rain and being parked for weeks on end may have been the cause.
Ordered a new wire frame # 2, used HV module and cleaned all the bussbars in vinegar/baking soda solution. Will be putting it back together as soon as the parts arrive.
195,000 miles, I'm the third owner. It appears as if this is the original HV battery. Each one measures between 7.4 to 7.6 range with no leaks.
The car still drove however, the electric motor would not start as it should when you accelerated, the ICE was the source of acceleration. Now, in reverse the electric motor worked as is should up to and past 20 mph.
This site is a wealth of information.
Thanks for all the help.

 

RE: Replacing the connector on the ECU.

Wonders never cease.
Something useful was written on Facebook today.
Amazing.

From the Facebook group: Prius DIY & How To
Posted by: Lars Olav Tollefson-Van Every
"Ebay has them, as well as does Aliexpress. They are NOT OEM parts. However, the OEM part appears to be a commonly available connector. Do a google search for 7282-5834. You’ll find many vendors eager to sell you a connector.
Then there's this one (FYI: It's the one I ordered before I found the other alternatives) : 2004-2009 Toyota Prius Hybrid Battery ECU Computer Voltage Sensor Connector Port | eBay
Also, Nissan uses this connector: 1 Set 22 Pin 0.7mm Car Auto Navigation Reversing Mirror Wiring Harness Connector Automotive Audio Cable Socket For Nissan|Cables, Adapters & Sockets| - AliExpress"

And: https://www.aliexpress.com/item/1005003640116126.html

Do a Google search for Toyota "7282-5834" and you'll find heaps of links for the connect that goes on the ECU.
The sockets are white (instead of orange) but look like they'll do the job.
Toyota "7282-5834" - Google Search

 

This is so freaking awesome! I can't thank you enough. The one on eBay is quite expensive though dang. And all the other ones don't solder directly to the board but I suppose I could just solder in wires. But dang if I'm soldering in wires I may as well cut the connector right off of the harness and solder those wires directly to the board!

 

SWEET, thanks good to know )

 

The negative post on the batteries are also leaking. Then humidity liquifies it and it spreads on the bus bars and down the sense harness to the ECU connector. There it can short and start burning. There are no current limiting resistors on the harness. Dr. Prius app is very useful but you need a good OBD module not some cheap ELM thing. good luck

 

Hi all,

Update on my 01 Prius. I ordered nickel plated bus bars, put it together and it drove fantastic. After I felt comfortable that it was dependable, I did a road trip Atl. to Miramar Beach, Fla. Less than a tank and averaging about 42 mpg, I was impressed. Return trip went well however I noticed the brakes felt like they needed more pressure to stop. Got home and the car sat for a few days. Made a short trip and on the return leg, the car died at my driveway. I'm getting codes CO226 steer front left, 236 steer front right , 246 rear and C1259 HV ECU. I've recharged the HV battery to try and start it, fail, had a battery tender on the 12V. Any thoughts on where to start? I'm also not sure which obd reader works best for gen1s and i phone. Cost wise. Any thoughts/input would be greatly appreciated. I will spend the time and effort on this car because of its condition and personal opinion of Gen1s looking the best.
thanks!

 

In addition to my above post, does anyone know if the listed codes possibly affect the regen system?

 

Yes, the eBay part is expensive compared to the AliExpress and other parts. However they do work, it's just getting them onto the board. I guess it really amounts to how badly you want to be able to unhook the battery sense harness from the battery ECU and keep it as OEM as possible? IMHO, that's not a bad thing. The eBay part requires some trimming of the connector pins to be able to be accepted in the PCB holes. The AliExpress pins have to be bent. So there is that. Of course, there are many other connectors that would work as long as you get a mating pair.

 

Have you posted this specifically in the Gen 1 threads, might get more help there. I'm in the Gen 2 group.

 

It just dawned on me that with all this fuss about these connectors what I'm going to do is solder the wires straight to the board! I thought dang the computer connector is $40 on eBay and doesn't even come with the other connector. That's way too much money so instead I would get the one from AliExpress and I would solder wires to the board and run them over to the plug area where I would crimp on the male pins and snap them into the connector. And then I would cut off the old plug from the sense harness and crimp on the new female ends and then I would have a fresh new plug. But Heck if I'm soldering wires directly to the board why don't I just solder the sense wires directly to the board and call it good! I'll give it a try

 

I’ve been watching this thread on and off for a few years now. I have a 05 gen 2 with 189,000 miles on it. In 2019 I rebuilt my battery pack using the newpriusbattery.com kit. I did have some corrosion on some of the pins of the connectors as have been discussed. During the rebuild I used several cleaning and protective products that I hoped would prevent further degradation. I was glad to see a posting for the ecu connector and I’ll be buying on to toss in the spares box for now. I also had the usual corrosion on the buss bars and replaced them with nickel coated ones. I used the Craig’s deoxit on all the buss bars and the connectors that I could fit a brush in and plugged and unplugged the connectors several times before a final wipe down and a bit of a blast with canned air. On the sense wires I used a conductivity enhancer Stabilant 22 on them. I’ve had very good luck with this product over the years. I used the smallest dab I could make on the connectors and wiped it with a fine optical cleaning cloth. Normally I would mix up a batch with some isopropyl as it’s frequently applied to socketed ic’s to increase conductivity for very low level signals without disturbing the device. It’s quite expensive for a 5ml bottle of the concentrate but you use such a small amount that it lasts me decades. When I was putting everything back together I gave it a lite spray of Craigs deoxit D5 that’s part of the shield series to hopefully counteract any further corrosion. I’m now a little concerned that this may attract dust and if the negative terminals are letting some material of some sort seep small amounts of something out of the battery that it may seal it into one concentrated spot rather than spreading out.
I’m now unable to remove the battery or even to climb into the back of the hatch do to a back injury. So I can’t pull the covers to check to see if I’ve helped or added additional possibilities for problems. It’s on my schedule to take it in next spring to have the HV battery fan cleaned and other maintenance tasks it that area, I’ll plan on having the mechanic pull the battery to inspect the condition of the ecu, connectors, buss bars and anything else that I can come up with at the time. I’ll put it on my calendar to revisit this post at that time for any updates even if it’s just that everything looks fine. It was good to visit the board after all this time and even see a post in the thread by Hobbit. I still use his recommended maintenance schedule that he posted 15 years ago. If you rebuild circuit boards or electronics in general you might want to try the Stabilant 22. I recently used it to repair a flaky board by just injecting the diluted version into some socketed components and connectors that was periodically generating errors. The pictures of the whiskers were enlightening.
After it’s been through maintenance I’ll post some pictures of what everything looks like, if I can remember to in my dotage.