HELP with Gen I 2002 Prius!

I do not understand how the car can be driven, if it is not READY. In any event the problem is serious and you should visit your local Toyota dealer so that the DTC can be read and a diagnosis performed.

 

This sure sounds like a bad traction battery but to confirm the diagnosis, we need codes.

GETTING CODES

1. Get it to a dealer - their service department has scanners that can diagnose the problem. Ask for a listing of the codes and bring them here for any backup.
2. Rent Graham miniscanner ($150 instrument deposit, $10/mo. rental) - allows reading error codes and critical traction battery values.
3. ScanGauge II ($175) - thanks to w2co and vincent1449p, we can use it to read HV and battery codes. From the battery we can read the 19 module-pair voltages and make and confirm a diagnosis. Works best with a well documented adapter.
4. Auto Enginutity ($400 and your laptop) - allows reading just about everything although some obscure data is marginal. Regardless, it has fairly complete coverage.
5. Techstream Lite ($1,200-1,500 and your laptop) - Toyota's offering for independents and do it yourself mechanics.
6. Over the counter scanners ($50-$200) - little more than junk, they barely cover emissions data and don't know about the different ECUs. If it doesn't show "ISO-9141 KWP2000," don't even bother. . . . junk.

FIXING BATTERY

1. Toyota ($2,200-$3,000) - turn key, one stop shopping.
2. Re-InVolt ($1,400-1,700) - two people can swap the traction battery in about 4 hours. I've been one of the two people and it isn't that difficult. Alternative, have an independent mechanic shop (or ask the Toyota service center if they do) to swap the battery.
3. Do It Yourself ($500+) - this is not a trivial task because you'll need: smart chargers, access to replacement modules, and some skill and instrumentation. It can and has been done successfully by technically skilled individuals but it is not a trivial, 'do it in a week' job. The car will be down during this period and there are new skills to master.

Bob Wilson

 

The only way to do anything is to scan the codes and pull data from the car.

Eric


Eric

 

This is what we've found:

• P3125 - generic code for the inverter. There are several dozen sub-codes associated with the inverter and to date, only the TechStream ($1,200-1,400) or shop scanners are known to read them out. However, w2co and vincent1449p have done excellent work and it may be possible to read out an inverter subcode. Without the subcode, you're faced with an exhaustive debug of each signal.
• P3009 - means there is a high voltage leak, usually in the traction battery. We know the older style modules have weak terminals and the electrolyte can make a path to the traction battery case. There have been some reports of clearing this but it is also the signature of a failing traction battery.

What is most needed is reading the voltages of the 19 modules or getting the maximum and minimum voltages. If the difference is 1.2 V or greater, then one module has failed and it is only a matter of time before the car becomes inert. Your options for reading these critical values are:

• Toyota service center (~$100) - ask for a diagnostic analysis and printout with all the codes and traction battery voltages. There have been some reports of difficulty getting this from some Toyota service centers.
• Graham miniscanner rental ($150 deposit, $10/mo.) - I have two available and can take a PayPal payment or invoice via PayPal for the $150 tool deposit. This scanner reports minimum and maximum voltages and block numbers as well as 50 other critical vehicle measurements.
• ScanGauge II ($175) - with an adapter and using vincent1449p table, this can read all 19 module voltages as well as minimum and maximum module voltages. The adapter can be made from ethernet parts bought at any hardware store or I can fabricate one for cost of parts ($20).
• Auto Enginuity ($400) - can read measurements for all controllers but not the inverter subcodes. It has mostly full coverage but their support is terrible and is leading their product into a bad place. You have to provide your own laptop with USB.
• TechStream Lite ($1,200-1,500) - provide your own laptop, a Toyota product.

As for the traction battery, there are seveal choices:

1. Re-InVolt or other known rebuilders ($1,400-1,700) - a turn-key solution that you or an independ shop can install. They deal with bad buss bars from corrosion automatically (i.e., no additional charge.) Now there are reports that some Toyota Service Centers can or will install their traction batteries but we've also heard less favorable reports. It really depends upon the local shop policies and not all are enlightened.
2. Toyota ($2,200 parts + $800 labor) - we've seen postings of even higher costs and it depends. Certainly replacing the buss bars ($200) is a reasonable approach.
3. Salvage battery ($500-$1,000) - a pure gamble as there is no assurance it will work.
4. Do-It-Yourself-Rebuild ($200-$1,000) - requires unusual technical skills, a work bench, and special battery charger ($150). This is not recommended for non-technical folks as there is a steep learning curve in electric and battery based technology.

As for the P3125 code, please measure the voltage of the auxillary battery with the car running. If it reads 13.8-14.0 volts measured at the terminals, the DC-to-DC converter that powers the 12 V battery is good.

Also, measure the 12 V battery before starting the car. If the voltage is below 12 V (~12.3 V is the target), then it is weak and this can induce a large number of pernicious symptoms. Replace the battery and then we can work on the car. The 12 V battery powers the control computers and if it sags too much it can induce a lot of random problems.

Bob Wilson

 

Actually, the codes as well as your symptoms point away from, rather than toward, the HV battery.

In the absence of diagnosis, knowing the three-digit information code or codes accompanying the P3125 code may help to narrow an educated guess. But without diagnosis, it's still a guess.

 

Excellent! The 12 V system is in good shape.

No, the codes would be readable but we've learned the commercial, over the counter scanners are . . . junk. There is no need to drive the car to get the codes.

Bob Wilson

 

I've got a quick idea, since your 12v system is good, and you have logged a P3125 - with the ignition to on (not start yet) is the inverter coolant pump running? You can see turbulence in the inv. coolant reservoir, and you may be able to hear the pump (just behind and slightly lower than the drivers side headlight. If no turbulence or pump noise, the inv. may have cooked, but if there is turbulence -never mind carry on gents.

 

We need codes to understand what is going on.

Our Prius has a suite of computers that operate the different systems. These error lights let you know something is wrong but they do not give us the specific diagnostic trouble codes.

Bob Wilson

 

Ok, the Graham miniscanner is on the way programmed:

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8
0	slot	1st line	2d line	usage
1	7	Batt. SOC %	Current A	traction battery charge and current
2	1	Aux Bat. V	Batt. V.	12 V system health and traction battery voltage
3	2	Max. Batt. Blk	Max. Batt. V	the best pair 1-19	and voltage
4	3	Cell Temp Max	Cell Temp Min	looking for overheating in modules
5	4	MG1 Temp	MG2 Temp	looking for excessive heat	MG2 should be less than MG1 unless MG2 has a problem or very high speeds
6	5	Engine temp	rpm	lets us know the engine is running OK	sorta
7	6	Min. Batt. V	Min. Batt Blk	identifies weakest module pair	if 1.2 V below max	is bad	stays on same module	is bad

There are about 50 different things we can look at but the Graham miniscanner is not easy to program, the first time:



It is 'modal' software so having this sheet handy will help. BTW, I forgot it is an RJ-11 (telephone jack) for the RS-232 signal. I had to use a resistor network to connect it to my Macintosh.

For more detailed information from the inventor:
ECROS Technology - Z8 Encore! Products

Thanks,
Bob Wilson

 

I figured with the manual online, it would be easy enough to pickup. As for the RJ11:

You'll need to wire up a connector so the Tx from the Graham scanner goes to the Rx of the 9-pin D and the ground pins. There is no handshake so CTS is not needed and the RJ11 Rx is used only for software upload. Please do not try to change the software as if this is done badly, the unit will become unusable.

When recording the data, it reports the "n" data items based upon the "n" of "Option 2" setting the to top from the current display line. When capturing data, I set line 7, 1, and 2 to the values I want to record. The unit comes up reporting these values but if you manually change the line displayed at the top, it also shifts the data reports.

The data is displayed <TAB> delimited with a relative time-stamp in seconds and single items per row. Save the recorded data as text and use excel or an equivalent spreadsheet and the data can get loaded into columns. It is not the easiest format but usable.

My experience is data recording is a 'stream' and of most useful if doing an engineering study. Lets get a diagnosis and correction of the Prius problems because if it stops running, there really won't be any engineering data. Once the repairs are underway, we can work out a swap. I have a second Graham scanner with a 9-pin "D" connector. I've never tested the 9-pin "D" because I don't have a computer with a connector.

Ok now we have something. You can clear the codes and this allows us to find out if they are permanent or intermittent codes:

• P3006 "Battery SOC Are Uneven" - the VMAX and VMIN exceeded. The signature of a failed module
• P3009 "Leak Detected" - typically due to electrolyte cause a current path to ground. Humidity tends to increase the leakage. Normally the all traction battery terminals are isolated from vehicle ground. In effect it has a built-in, "ground fault" and it has found a leak.
• P3026 "Battery Block # Malfunction" - the modules are numbered 1-19 and P3011 is block #1. So this means block#16 has a problem

For confirmation, use the Graham scanner and touch the middle button so "01" shows. Then tap the right button until the minimum voltage is shown with the block number. The Graham scanner can not survey all 19 module pairs. However, it does report the minimum voltage and block number and the maximum voltage and block number. This is enough to confirm the diagnosis.

There are a total of 14 items that can be displayed by cycling through the 7 lines. The remaining 50 items can be displayed by programming new data fields for any of the lines, replacing the others.

This typically is seen in the morning when the car is first started. However, a failed or failing module can lead to higher voltages. I typically don't pay any attention to total battery voltage or even SOC as long as the VMAX and VMIN for the 19 modules are within ~0.3 V. In a series battery, balance is the first priority.

What happens is a 'more charged' module when being charged is driven into overcharge which damages it by generating gas and high temperatures. During discharge, the 'less charged' module is reverse charged which destroys it. By having all modules in equal charge or close enough so the guard-bands keep them in operating range, the battery returns years of service.

Sad to say, the Graham scanner won't read out the 19 monitored, pairs of modules. However, it isn't necessary to diagnose a failing battery.

The ScanGauge can read out the 19 voltages and module-pair resistance. However, it doesn't handle the engine parameters like the Graham scanner. Also, the ScanGauge has its quarks too although thanks to w2co and vincent1449p, we are finding ways to work around them.

Please cycle through the other lines, especially looking for the VMIN and block number.

Also, clear the codes and see what comes back. I suspect you have hard traction battery failures which means 'the clock is ticking.'

On the traction battery, you have options:

• Toyota replacement ~$3,000 - if you are not 'do-it-yourself', this returns the car to operation and you're good to go with a one year warranty.
• Toyota battery, you rebuild, $2,400 - recently an owner in NY ordered the replacement battery and swapped the electronics to replace his pack. He reported it took about 5-6 hours, which seems a little 'optimistic'.
• Re-InVolt battery, shop swap, $1,400-1,700 + labor (4-6 hours) - there is a growing list of independent hybrid shops and some enlightened Toyota shops that can do this work. One year warranty.
• Re-InVolt battery, you swap, $1,400-1,700 - either old style NHW11 modules or newer NHW20 modules. Personally, I would go with the $1,700 pack as the NHW20 modules are significantly better than the NHW11 modules. One year warranty.
• Other rebuilders - I understand Lucsious Garage in San Francisco does this but I don't have the details. There are others but I've got no direct experience with them and can't really say one way or another . . . sorry. BTW, Arts Automotive is also well known shop.
• Self-rebuild - this is a technically challenging task and should not be undertaken lightly. You'll need special chargers, a good work bench, and time measured in weeks to do the job right. I've seen a significant failure rate, ~50%, with those not having adquate workspace, tools and technical background often having poor results. But I'll offer what little advice I can to anyone. Just don't underestimate the effort.
• Single module swap - well if you are trying to sell the car . . . uck. It means the next owner will probably be here in three or four months.

Bob Wilson

 

The maintenance manual is pretty detailed but I suspect if you Google around, you can find somewhere it has been photographed.

I helped Daryl swap his and it was pretty straight forward. Just remove the rear seat and the covers in the trunk. The connectors are on the driver side and mostly easy to remove. There is one tricky interlock but otherwise, no real show stoppers.

Any luck on the other lines, in particular the minimum voltage module-pair and block number?

Bob Wilson

 

Not in this forum. Start here: Installing a Prius HV Battery

 

Some really great information and detail Bob. Hopefullly I will never need it, but it makes for facinating reading. Thank you for your effort.