We just bought a used 07 TCH, that was popping a lot of error codes about the battery. Dealer we bought it from didn't want to do the work on it, and after some research we decided that we could fix it on our own. The car still ran quite well. It actually ran for two weeks with all of the error lights on. The only issue it had was at low speed the vehicle would randomly shut off and the amber light would come on the START button. Pulling over and putting it in park and restarting it would solve the issue and we could continue on but we still wanted to fix that problem.

We finally get ready to do it and disconnect the 12v, disassembled the HV,
and we find the most corroded connectors ever. We clean those, and the bolts. We tested the cells, and all but one were reading properly at 7.9v. While reassembling the battery, I screwed up and over-tightened two of the bolts and broke the terminals off. We went and bought 3 new battery cells and tested them. They were at 7.9; all good. So we reassemble and reconnect the battery, and the car won't start. it turns on! The dash comes on, the radio will turn on... in fact, it seems like everything comes on except the traction engine.... We test the the 12v, and it's reading around 11.7v, which dropped near 5v whenever we tried to start the car. We took it to a battery shop who confirmed that it was dead. Also confirmed that it was the original battery, sold with the car. So at this point, its a 11 year old battery.... definitely needed to be replaced. So, per the advice from one of the other threads in this forum, we bought an optima red top d35. It's reading the right voltage and all that, so we connected it back to the car and it still wont start. It still turns on... but won't crank.

We have checked at least 10 times to make sure that the orange HV connector has been put back in properly!!!

Our next move is to re-pull the HV pack and try to recheck/retest everything so we're hoping someone can help us.

 

Your answer is in the codes. Read the codes. Report back.

 

I don't have a way to get the codes right now, since it won't start and Id really rather avoid having to pay to tow it to Toyota. The dealer read the codes when he sold it to us, and told us to fix the HV battery, and that's all I've got.

Is there any sort of trouble shooting I can do without the computer? Maybe a fuse is blown, or maybe there's some other commonly screwed up step in battery installation that I haven't been able to find out about yet.

 

Get a BlueDriver code reader (it's about $100), it's probably the cheapest way to read the Toyota proprietary codes. A generic OBD II reader cannot do it, nor can your local parts store. If you're going to be doing your own repairs on your TCH, it's pretty much a necessity.

Have you checked the output voltage of the battery? Connect your voltmeter leads to the + and - connection bolts. And be very careful, that's over 250V.

Also, be aware that the 12V battery does not start the engine. The TCH doesn't actually have a starter, it uses the traction motor to do it. If you look at leads leading to the 12V battery, you'll notice that they're not very thick - the 12V battery is only responsible for the dash and accessories.

 

MiniVCI (< $30) and your own 32 bit laptop will give you dealer level diagnostics.

ORielly uses Bosch code readers that can pick up most of the Toyota codes.

Don't bother checking voltage at the battery. They are isolated from the car by a relay. If you have voltage there, you'd be in ready mode, and the car would start.

The 12V provides ALL 12V power at start up including the dozen or so computers, not just dash and accessories, nor does it use the traction motor to start the car. It uses MG1. The traction motor is MG2. MG2 can't start the ICE as it has no connection to the ICE.

You need to get past the idea that these can be fixed without reading codes. If you're not going to make an effort in that direction, just tow it to the salvage yard or put it up on craigslist. You shouldn't own it.

This is basically what you're saying: "Hey guys, I have a problem with my car. I know my car is telling me exactly what is wrong, but I want you guys to guess what's wrong for me."

Good luck,

Steve

 

Assuming you're correct (and I assume you are, as you seem to know a lot more about this car than I do), there is another way to check battery voltage (actually, a couple, but this is safer). If you remove the rear cover of the battery pack (the one that covers the electronic modules and relays, not the second one that covers the batteries themselves), you'll see two thick wires (one orange, one black) coming from the battery and connecting to a module using plugs. If you unclip those plugs, you can insert a probe from your multimeter into the hole in each plug and get a reading (it's a tight fit, and make sure it goes in all the way). Ensure that the safety plug is fully plugged in and engaged (remember that this is a three-step process: (1) plug in, (2) flip down, (3) slide).

 

The cover is in the front of the battery, not the back.


Both cables are orange, not orange and black. They have a small strip of black and red tape indicating polarity.


Otherwise, your method is valid.


He clearly stated that he checked that the orange plug was installed properly (at least 10 times).