Gen 2 ... Dr Prius says two blocks bad

week three on this - trunk and seats dismantled for the fourth time....

I removed the battery sensor loom and checked the contacts on the sensor loom on the front of the battery - I put a pin into the tiny sockets on the plug and checked each one - the avometer beeped happily throughout. All the battery modules are the same voltage..

There are no signs of burning either inside or in the socket of the unit

https://i.ibb.co/vcNhsVs/20240403-174518.jpg
https://i.ibb.co/8YjZbGT/20240403-174226.jpg
https://i.ibb.co/DMZgXp7/20240402-172119-1.jpg



I did find a control unit on ebay from a bloke called Abdul in west london for £220

he said no returns under any circumstances - which is contrary to ebay policies

I then used the part number mentioned above to find a proper battery specialist called Mathew in Bradford

Toyota Prius Gen2 2004-2009 | 1-Diagnostic

who is selling the same unit plus loom for half as much and they are happy for me to send it back should it not solve the problem.... I am now full of hope again



PS my part number is 89890 47092

but the part from bradford is

89890 47090

the bloke from Bradford said that he will make sure that the one he sends is compatible with mine... which is very nice of him

Dylan

 

Fixed....

as Bryan said, the problem was somewhere around the Battery management computer box, sockets and the tiny wires along the front of the battery.

I could not find spares until I came across 1 Diagnostics which is in Bradford 200 miles away.. Apart from the Toyota dealer in suffolk no-one else wanted to touch the car....around the big cities in the UK there is a sort of hybrid infrastructure because Prius is the chosen car of the Uber drivers. Over here on the coast there are far fewer elderly Prius cars around.

Hybrid Batteries | 1-Diagnostic Ltd | United Kingdom


They were advertising gen 2 and 3 BMUs on ebay for £102

. I ordered a gen 2 and a gen 3 turned up. Bumma.

So I emailed them with a snap of the inside of the battery along with the part number -

I sent back the gen 3 bmu and they they sent me a gen 2 BMU with a slightly different part number from mine but Matthew and Conrad at I diagnostics said it would work.


It was really nice to talk to people who knew their stuff.

Matthew also sent the wiring loom that had been cleaned up. Earlier I had a go at cleaning up the old ones using vinegar and sandpaper (from one of the countless youtube videos I watched ) - but clearly not aggressively enough. In its initial state there was was some corrosion on the pins at the BMU - but I was getting a good connection along the wiring loom to the plug - clearly not good enough though.

This is our only car so between repair periods I had to re-install all the boot gubbins so that I could drive the car.

The bits turned up delivered by DHL within 3 days and carefully packaged. Really imressed with the mathew and his colleagues.

By the time of the final repair I was delving into the boot space for the fifth time - there are some excellent vids on the web of how to do this - but I am getting really fast at it.

For an old bloke this has been a steep learning curve.

I worked as a tractor mechanic for several years - not much electrics in those days - just replacing brushes on dynamos was all I did in that department. I am used to spannerable repairs where I can hear, feel, see or even smell the fault.

with ev batteries I was replacing what looked like functional parts with what also looked like functional parts. I was a bit sad about the corrosion - although I do live close to the coast in a damp country.

Dr Prius seemed a bit imprecise about the fault and lead me first of all into relacing four of the battery modules.

So thanks for helping me get the car going - especially Brian . Next time I have a battery problem I will just buy a complete refurbished battery from 1 diagnostics

I did the battery longevity test and it came out at 60 per cent - which is okay for a 135,000 mile old car. I will redo the logevity test once the BMU has had a chance to do its stuff with balancing the cells.

Dylan


PS - how long can you drive a gen 2 rius with a duff HV battery ?

- the car drove pretty well - it was noisy in traffic but with a gentle thrttle foot I was still getting 58 mpg on long motorway trips at 65mph - one I hit traffic the mpg came down to about 20.