Japanese Gen II Prius with HV Problem

It is difficult to tell from the display what is wrong even with the English version of the display as it only tells you there is a problem, not what it is.

I would start with checking the 12 volt battery voltage with a meter with the car in ignition on mode (not ready) two pushes on the start button without the brake pedal, and report back.

Does the HV battery display fluctuate quickly from high to low charge and back, and do you hear the rear cooling fan running drawing air in by the rear seat?

Can you tell us what country you are in as at the moment? I assume this car is an import to somewhere. It is very helpful if you put your country in your avatar.

Someone at some point will no doubt chime in with a translation of your screen from Japanese.

John (Britprius)

 

Did you check the battery on load:- ignition on (not ready) with headlamps on. Then check voltage. The Prius throws all sorts of trouble codes if the battery goes below 10.5 volts at boot up, so check this out first.

It is possible that IG1 and IG2 relays are not turning on if a low voltage is present under load at start up this could also cause low accumulator pressure. Circuit diagrams for the two relays are below.

This is not a HV battery problem, more likely a 12 volt problem. Do not check the voltage in ready mode as the battery is then on charge from the HV battery.



John (Britprius)

 

The Prius battery is notorious for not recovering from being deeply discharged and that is considered to be at 50% discharge or around 12 volts and fully discharged at 10.5 volts. So at 6 volts yours probably has been destroyed, it should also not be charged at more than 4 amps "see the label on the top". At over 4 years old is due for replacement anyway.

John (Britprius)

 

The Japanese message probably says something like :- The parking mechanism is at fault please park on level ground and select park. Or words to that effect, this is very common with a poor 12 volt battery. Be very careful when jumping the Prius battery as a wrong polarity connection even for a second can be very expensive.

The voltage you are measuring suggests you are checking the voltage in ready mode
"on charge". A good Prius battery on load "not on charge" would measure between 12 and 12.3 volts

John (Britprius)

 

Living in the UK it is difficult for me to give advice on batteries available to you but check out Exide Edge battery (5year replacement guarantee) and read my post.

Fitting mobility 12volt AGM battery.

John (Britprius)

 

The exide battery is part number FP-AGM51JIS is a direct fit battery for the Prius. It has a longer guarantee than the Optima and has a higher capacity at from what I can find is about $150 in the US.

I am personally not an Optima fan, but many here are as I consider it to have poor space utilization and is over priced.

In the UK the Optima battery to fit the Prius is £186 + 20% VAT making it £223 or $357. There also have been quality issues posted here on PC.

Whatever battery you choose from the Optima or the Exide ranges the battery tray fitted in the car must be the larger one "two sizes fitted" Toyota part number 74440-47020

What battery voltage did you find on load with your Prius as we all are interested in the outcomes of problems such as yours, helping the pool of knowledge available on PC.

John (Britprius)

 

To clear the codes disconnect the 12 volt battery for a few minutes. After re connecting you will need to boot the car twice before it will work correctly.

Connecting a battery in parallel with the Prius battery should enable the car to go into ready mode without giving fault codes if no faults actually exist, and codes have been cleared.

The HV battery can be charged by, making the car ready,putting it into drive, hold your left foot on the brake, and press the accelerator with your right foot.

This will make the engine run and charge the battery with MG1. May take 5 minutes to get battery up to 5 blue or 6 green bars. You will not do any harm doing this.

If the fault codes come back with a known good battery connected "once codes have been cleared" it is likely you have some other problem (most likely skid control ECU), but again I stress it is most important that you know there is a good 12 volt battery powering the car at the time it boots up the computers, as this is the time that the spurious fault codes are generated.

I did realise there is a time difference but do not know how much, 6hrs? behind GMT.

I was hoping someone would have done some translating by this time as that "may" help. Still let me know how things go and we can take it further.

John (Britprius)

 

Be aware some jumper leads only connect through one jaw of the clamp so connection to the Prius jump point in some circumstances may not take place.

John (Britprius)

 

Maybe the brake accumulator pump.

JeffD

 

The brake accumulator pumpnoise is normal - so there is nothing to check. The car runs a pump to put pressure into the brake accumulator so that the next time you use the brake you will have "power" brakes. It's normal for it to run a few minutes after the car is turned off. This is why you don't want to do brake work with the 12v battery connected.

Good Luck

 

The Japanese seems reads your HV battery had encountered some abnormal condition, message advised you to pull over and stable the car and contact your dealer. However per your second picture,the HV seems working OK. So per other members said,check youe 12V battery or change to a new one. The Optima Yellow cap is a good choice.

 

The Prius does numerous things on it's own without the fob in the car one of the reasons you need a good battery, the accumulator pump running is one of them. This according to my measurements will pull from 8 amps rising to 16 amps "as the hydraulic pressure builds up" with a good battery.

A poor battery will limit the current available and the battery voltage under load will fall considerably causing the sort of problems you had. The computers and display screen pull about another 10 amps at boot up.

When you open the drivers door, this will often start the brake accumulator pump loading the battery before you even get in.

The security system also puts a small continuous drain on the battery. I am sure you have now found your problem is the 12 volt battery and replacing this will eliminate your problems.

Do not work on the brake system without disconnecting the battery and pulling the two light blue relays in the fuse box under the hood, this includes pad changing. You also cannot bleed the brakes without the suitable computer equipment "Autoenginuity may do this", and my advice would be do not touch the brake hydraulics unless you need to. Below is the hydraulic circuit to give an idea of the complexity.


Keep us informed how it goes.

John (Britprius)

 

When you first drive the car from cold do not be surprised or alarmed if the HV battery display goes down to 2 purple bars. This is not unusual as the Prius uses the battery to power the car when the engine is cold to reduce load on the engine and keep emissions down.

It will quickly recharge itself as you drive. The computer will try to maintain a charge level of about 5 blue bars.

Any questions just ask.

John (Britprius)