2006 CEL question

What city are you in?

 

You're not screwed.....you just need 2 new modules to replace the bad ones. Should've done this from the very beginning. Other than wasting some time, it's really not too late

 

Make sure that the no load voltage is at least 7.6; 7.7 or above is preferable because that would indicate the module had been charged in the last week or so.

Bring a halogen bulb with you and a multimeter and record the time it takes for the voltage to drop to 6.8. Connect the high and low beam filaments to get a 120W load. A good module should be capable of slowly decreasing to 7 volts in 20 minutes or more - preferably 25 minutes. That depends on whether or not the module had been charged recently. A module that had been sitting on a shelf for a while might only last 18 minutes before reaching 6.8V.

If the voltage decreases to 6.8V in less than 12 minutes, it might have low mAh capacity and you might not ever be able to get it back to 4000 mAh after discharge/charge cycling. The module could be undercharged but if it was the no load voltage should not be more than 7.6V.

 

Dead are those less than 7V. Yes, you should test all 28 of them - it's easy to do once you have the case open.

 

Actually both. No load sorts out the obviously bad ones - those with a failed cell in the module. The load test lets you know which ones are weak and likely to fail next. People who don't locate and remove the weak modules usually end up playing whack-a-mole with their HV batteries.

 

Glad to help as others here have done the same for me.

 

I'm on my way to work right now but I'll describe what I consider the best and easiest way to swap out and rearrange modules. I'll do this later today.

 

zytra,

I don't have any photos or diagrams to go with the descriptions I'm about to share with you. It is your responsibility to take photos at each step of disassembly so that you will know how to reassemble everything
correctly again. If you neglect to take an adequate number of photos you might be SOL later.

a) Dorman made an excellent you tube video showing how to remove the battery from the car - Find it and watch it several times so you know how to safely disconnect the orange cables from the battery.

b) Purchase and wear Class 0 lineman's gloves and leather gloves that cover them. Don't skimp here, it might cost you dearly.

c) Wear safety glasses or other suitable eye protection.

d) Buy or borrow a 1/4 drive torque wrench to re-tighten the 56 nuts on the modules, which is very important to get right. The torque values are provided in the service manual which is the next thing you should have.

e) Locate the service manual chapter HB - P112 Hybrid Battery Control on the Internet and download it. It does not have all of the diagrams you'll need to remove the module assembly from the bottom of the case but it has most of them. Read pages 101 - 109, 113, 115, and 123.

1) Place the HV battery on a sturdy table/workbench or on a wheeled cart that can easily handle 100 lbs.

2) Remove the top cover of the case. Reinstall as many of the fasteners as you can back onto the bottom of the case so you won't lose them.

3) Flip the battery upside down.

4) Remove all 28 fasteners that hold the modules to the bottom of the case. Don't worry, the modules are still clamped firmly together as a group - they won't go anywhere. Place all 28 fasteners in a plastic bag separate from any other fasteners.

5) Flip the battery right side up again.

6) Remove the two 10 mm nuts - one at each end of the module assembly, which is the first step of removing the bottom of the case from the module assembly.

7) Remove the black protector covers from the buss bars on each side of the battery. The service manual identifies the rear side buss bar as the junction block and the front side buss bar as the frame wire. Front and rear side mean of the car, not of the battery.

8) You should remove the two nuts that fasten the service plug grip to the modules on the junction block first before removing any of the other 54 nuts that fasten the buss bars to the 28 modules. you should also be wearing your Class 0 gloves and the leather gloves while doing this since you are working with high voltage even though the service plug has already been removed.

9) Remove the 28 nuts from the rear side buss bar and remove the buss bar. Place the nuts in a plastic bag separate from any other fasteners. Whatever you do, don't lose any of these 56 nuts. If you do, you'll need to order replacements from a Toyota stealership.

10) Remove the 28 nuts from the front side buss bar starting at the ECU end working back toward the cooling fan side. You should remove the ground wire from the module furthest away from the ECU last. This is the #1 module by the way as the modules are numbered 1 to 28 from the cooling fan side to the ECU end. You'll notice that you won't be able to remove the front side buss bar because it's still connected to the ECU end of the battery assembly.

11) At this point you're ready to disconnect the front side buss bar from the ECU end. You will need to remove two power cables and a ground wire. Actually there are several things you will be disassembling here but in the long run it will be worth it, believe me. You will see which of the cables and connectors need to be removed. I won't go into detail because it's too difficult to describe without photos. And you need to take several photos of the ECU end at different angles so you will remember how it all goes back together.

12) Once you've removed all the cables and connectors from buss bar to the ECU end you can remove the front side buss bar from the battery.

13) Next, there is a green wire at the top of the module assembly that you should disconnect. You don't absolutely need to remove it but I don't like wiring in my way when swapping and re-arranging modules. The green wire is the intake air temperature thermistor.

14) Now you can lift the battery assembly off of the bottom of the case.

15) I almost forgot, you need to (or should - up to you) remove the three battery temperature thermistors at the bottom of the module assembly. Take a few photos so you will remember where the thermistors are connected. Then remove them from the module assembly. The connectors to the ECU for the battery temperature thermistors (and the intake air temperature thermistor) were removed in step 11.

16) If you've done this correctly to this point you will be left with 28 modules, two plastic end caps, and eight bolts and four steel tubes that hold the modules together and that's it.

17) You're ready to start testing the modules now. Before that, identify each module from 1 to 28 with a permanent marker at both ends of the module. Check the no load voltage of each module first to locate and eventually swap out the obviously bad ones - those less than 7V. Then, at the very least, you need to run load tests with a halogen bulb with the high and low beams lit simultaneously to generate a 120W load. Monitor the voltage drop as the battery slowly drains from its no load voltage to 6.8V - a value I decided upon because I've noticed that the voltage tends to drop off quickly from there so 6.8 is a good stopping point. 7V can be the stopping point as well. Good modules should last 25 minutes before the 6.8V endpoint if the modules have a relatively fresh charge on them. If the 28 modules had not been charged in a week or more then some self discharge has inevitably occurred which might affect the capacity draw down time a little. Modules that last no more than 12 minutes to 6.8 are either weak or are undercharged. The no load voltage is somewhat helpful here in that if the no load voltage is 7.2, it's likely that the module is undercharged. This, in itself, is a red flag though. None of the 28 modules should have voltage that low if several others don't as well. Weak modules also suffer from high self discharge in addition to low capacity. Once you find the weak modules - consider replacing them instead of trying to bring them back up to the most capacity that you get out of them. Some people have had success doing this, others like me, not so much. I have not had success mainly because I don't own (nor want to own) the requisite number of chargers needed to do this which is explained in the next step.

18) The ideal thing to do after the load testing is to run discharge/charge cycles on the modules with several balance chargers to get back as much as the capacity you can squeeze out of them. Important note: any time that you're charging the modules, they need to be tightly clamped together. I like to keep all 28 modules together in the as-assembled state I received them in. In fact, I don't loosen the bolts on the steel tubes that compress the module assembly unitl I'm ready to swap out the bad ones and reshuffle the good ones. I've found that the nimh cells respond best when the charging rate is low - no more than 650 milliamps per 6500 mah capacity module. It takes a long time to fully charge each module this way and to do this three times on 28 modules without at least the equivalent of 10 balance charger channels would take forevah. But it is the safest way of charging and there's almost no chance to overcharge a module and make it bulge too much. Module bulging is bad! Avoid doing it. The discharge rate is not as critical. I used halogen bulbs to speed up each discharge cycle. A grid charger to discharge/charge all 28 modules at once is another acceptable option and is about the same price as two four-channel balance chargers. Chances are excellent that the grid charger will balance the capacities of the 28 modules sufficiently such that the 14 block voltages will be nearly the same as what can be achieved with individual module charging.

19) Okay, you've completed balancing and optimizing module capacities the best you can and now you're ready to shuffle the center modules to the outside and vice versa. This is a good strategy because the center modules have been exposed to higher temperatures since the battery was manufactured. Moving them out to the periphery of the assembly is a no brainer IMHO and doesn't take very long when the battery has been disassembled to the point described in step 16.

20 Now you should match capacities for each block as best you can. In my opinion, voltage drop and capacity drain occur at practically the same rates for a given module. I match pairs of the strongest capacity modules with the weakest ones first to see what the average capacity of these blocks will be to determine what the average capacity should be for all 14 blocks. Ideally, each block capacity should equal 6500 mah. On an older HV battery you'll get 5000 mah or less if you didn't bother to optimize the capacities with 3 or more discharge/charge cycles. Voltage drop block matching again is essentially the same thing. Match the strongest voltage drop with the weakest and so on until the block voltage drops are as close as they can be for all 14 blocks. That way when the HV battery is being used in the car, the voltages and voltage gains/drops of each block will be as close as possible to each other when the voltage increases during regenerative braking and decreases during acceleration. In fact the largest voltage difference between blocks will be when the HV battery current is greatest - 100 amps!

20) Swapping and reshuffling the modules is really easy. The module sides fit against each other like Lego blocks. As long as you have the positive and negative terminals of adjacent modules next to each other at both ends, the modules align against each other perfectly and that perfect alignment continues as the modules are placed side to side as an assembly - again like stacked Lego blocks. The only tricky part is making sure the plastic end caps are in the correct positions relative to the outer modules (#1 and #28). One really important thing is to make sure the length of the re-tightened assembly is exactly the same as it was before you loosened it. That means you should measure the assembly length before you loosen it - unless you enjoy the challenge of getting the holes on the bottom of the case to line up with the modules again. Any volunteers? I didn't think so.

21) Okay, you've gotten the bad and weak modules out, have reshuffled the rest and have tightened the assembly back to its proper pre-loosened length. Congrats - you're finally ready to work backward. Recede from step 15 to step 2.

22) Hooray! You did it ! Now the only question is how long will it function until the next P0A80.

 

#6 I believe those are 12mm

Good write up. Should be a sticky......with a high voltage warning