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Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4433
Experience:  Toyota Master Tech, ASE Certified
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My Toyota highland can not start. It shows "check HV hybrid

Customer Question

My Toyota highland can not start. It shows "check HV hybrid system.
I removed the seat and open the carpet. On the top of the battery cover, there is a small plate with 2 bolt, it's a check window. I opened the plate, checked the voltage with a Voltage meter, there is no Voltage between the two main cable. I open the complete battery cover, checked the battery voltage (input for this main junction block), the Voltage is 300 V. I checked individual battery, the voltage is 10 V, there are 30 battery pieces.
I start the car again and check the voltage between the two main cable, there is no voltage.
shall I replace the main junction block? ( it's $290) On the main junction block, there is two big NAIS relay and a small NAIS relay, and a 40W 30oum resistance.
Submitted: 2 years ago.
Category: Toyota
Expert:  Ted Ritter replied 2 years ago.
Thanks for posting
When you get the message "check hybrid system" the first thing to do is to connect a diagnostic computer that can access the system to give you some DTC information, did you do that?
The reason you are not reading voltage at those two main wires is that each one connected to one bank of cells with 150 volts each, if you measure across you will see zero volt potential.
Customer: replied 2 years ago.
Hi Ted, Thanks for your reply.Do you think the main junction block could be not damage even if there is no voltage between the two cable?I have not a diagnostic computure to check it. I checked the battery, the voltage is ok. only have not meaure the voltage at the out put of this main junction block.
Can you give me some advice where should I check and fix the problem?I am veyr appreciated for your furthere advice.LI
Expert:  Ted Ritter replied 2 years ago.
Because there are many reasons for the "check hybrid system" message it is almost impossible to guess what the problem may be and where to even start, I don't think the HV battery is the problem, this is a very complex system which is going to require specialized equipment to diagnose so the first thing is to always access the car's computers and retrieve the diagnostic code numbers, as a hybrid certified technician this is what we do first, please find a way to get this information, I highly recommend getting a Toyota dealer involved. You didn't mention what year the Highlander is but if there is a problem with a major component of the hybrid system it may still be under warranty, the main battery is under warranty for about 120,00 miles or ten years, other parts up to 80,000 miles or five years, depending on what it is.
Customer: replied 2 years ago.
Thank you Ted.I thought the problem was from the main junction block. I will check the voltage between the cable to one of the bank to read a 150 v and also aanother cable to another bank with 150v. If I can read the 150 V, that means the jucntion block is not damage, am I right?If the junction block is not damage, I have no other idea. Then I will pull the car to the dealer. My highlander is 2006, 220,000 KM ( 136,700 mile) . the dealer told me the battery replace need about $5000.
that's the reason i want to try.any way, would please tell me if i need replace the junction block? should i read 150 V between the cable to the bank on each side?Thank you again.
Expert:  Ted Ritter replied 2 years ago.
Yes that is correct. each bank should show 150 volts when measured to ground, when the orange safety connector is installed the circuit is completed between both cell blocks to result in 300 volts total.
Customer: replied 2 years ago.
Hi Ted,
In case i could not discreb clear, let me name this. The input wire, connet to two pole of the battery, input with plug to the junction block. The output, out put from the junction block, mount with nuts on the block.I can read the voltage between the two input wire, is 300 V. The voltage between the two out put cable is Zero.
You mean, I should read between one out put cable to an input cable, should be 150V. if there is 150 v, that means the junction block is not damage. Is it right?i am appreciated for your further reply.
Expert:  Ted Ritter replied 2 years ago.
Yes that would be correct.
Customer: replied 2 years ago.
Thank you Ted. I will try tomorrow.
Expert:  Ted Ritter replied 2 years ago.
You're welcome