Need help diagnosing strange MDF display along with possible lost of electric power

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by donl73, Aug 28, 2009.

  1. donl73

    donl73 New Member

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    Short version of the story is that '05 Prius with about 92,000 miles and has 6yr/100,000k extended warranty. Recently sudden 7-10 MPG drop without change in driving habit/behaviors. MDF energy monitor at time showing electric motor is putting out electric power and charging the battery at the same time. Lost in power resulting in ICE almost always on. Dealer's service department thinks there is nothing wrong with the car. I really need to figure this out before extended warranty expires.

    Could it be that there is something wrong with the electric motor or hybrid battery, resulting in the lost of electric assist, and causing the ICE to always start?


    Now the LONG version of the story.

    I live in Los Angeles and have a '05 Prius with about 92,000 miles on it. There were service events leading up to this point and I'm not sure if its relevant or not so thought I'd list it out anyways.

    On 8/2 (Sunday), I brought my '05 Prius to the dealership for scheduled 5K miles service. I'm sure not everyone would agree with this, but I do my service at the dealership hoping to increase/retain the resell value.

    At any rate, upon dropping off the car, the service personnel suggested the throttle plate cleaning. Considering I was getting close to 100k, I went ahead and agreed to it. After the service was done and I was on my way home, I noticed the ICE revving even when I was at full stop at the traffic light. When I got home, the ICE was still revving itself after I've pulled into my drive way and after I've put the car in park. Since I picked up the car after their service department had closed, I couldn't just bring it back and have them check on it immediately.

    On the following day (Monday), I called the dealer and was told to bring it back for checking. I made an effort to leave work early and brought it back on Tuesday. After waiting for about 1-2 hours, they told me their service tech didn't properly clean the throttle plate the first time, but they've done it now.

    Got on my way thinking everything is now fixed. However, I've started to notice an increase usage of ICE compared to before the initial 8/2 service. Almost to the point that I can't touch the gas peddle without the ICE turning on. At first, I thought the dealer didn't set the tire pressure correctly after rotation and didn't think too much of it. However, after dragging my feet and eventually checking the tire pressure on 8/15 and discovered it was not the problem. I emailed the dealer service manager on 8/17 and got no response so I called on 8/24 and was told to bring it back in for checking. Brought it back on 8/25 and left the car there for 1 day and 2 nights. On 8/27, the dealer called back and swears they can't find anything wrong with it.

    I picked up my car on 8/27 and on the way home, I started noticing something I've never seen prior to the 8/2 service on the MDF. The MDF energy monitor at time shows the orange arrows to the wheel, indicating electric motor is putting out power, but also green arrows to the battery, indicating its charging at the same time. The problem of ICE always turning on still exist. At times the hybrid battery don't seem to want to charge. I've attached a picture for review.

    Thanks for reading the LONG story. Please help because I really need to figure out what's wrong before my extended warranty expires, since the dealer appears to either not notice or don't want to acknowledge the problem.


    Thank you!!
     

    Attached Files:

  2. donee

    donee New Member

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    Hi Donl73,

    That is a completely normal low accelleration display. If you push harder on the gas the arrow to the battery will go out. And even harder a yellow arrow from the battery to the motor will come on.
     
  3. efusco

    efusco Moderator Emeritus
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    I'm willing to give the benefit of the doubt to the driver here considering 92k miles of experience driving the car I would think he knows normal behavior.

    Are you seeing any wide swings in the battery SOC...full green to low pink without any dramatic terrain or conditions?

    How far have you driven and how have you determined the loss in fuel economy? I know I'm pretty sensitive to minor changes and can tell when a tire is low on air b/c my glide isn't right and such. Are you noticing anything of that sort?

    Have you checked the oil level--could they have overfilled? Have you checked tire pressure to make sure they're where you like it?

    Other than the throttle body cleaning and oil change did they do anything else?
     
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I have to agree with Evan on this one (it's rare but it happens). With 92,000 miles of experience, don knows what he's talking about. Like Evan, I can tell when the slightest thing is wrong with my '04 so when Don says something's wrong, I'm willing to bank on it.

    This might have crossed your mind before, but are you willing to take it to a different dealer for inspection? I'm working on the principle that your dealer has checked everything they can think of. Now it's time to find someone who can think of new things.

    Sorry that your first post is related to unusual performance. Keep us posted on your status and welcome to PriusChat! :welcome:
     
  5. richard schumacher

    richard schumacher shortbus driver

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    Possibilities:
    - they ran down the battery causing transient unusual behavior, and now you're hypersensitive to everything the car does (your pardon, sir, but if during 92,000 miles you never noticed the engine charging the battery and driving the wheels at the same time you may have overlooked other normal things as well)
    - they damaged the mass airflow sensor (MAF) while cleaning the throttle plate.

    Wait another week and see what happens. If no change take it to another dealer.
     
  6. hobbit

    hobbit Senior Member

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    Ask them if they actually dismounted the throttle body to clean
    it. They could have screwed up the TPS position if they'd taken
    that off to get to the drive-motor gearing to lube it. It has
    to be put back EXACTLY as it came off, as the engine ECM doesn't
    learn a new position range for the thing.
    .
    _H*
     
  7. donl73

    donl73 New Member

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    Donee: in my past experience with my '05, during low acceleration, usually it has the ICE flowing to the tires and and electric motor, while battery flowing to the electric motor, which then flows to the tire as well. I don't recall ever seeing this type of display before. Besides, I don't recall ever seeing the ICE trying to charge the battery during low speed acceleration from full stop, when the car needs power the most, especially when the battery is not in the pink. I will try to take a video of the display tomorrow and post.

    efusco: the SOC seems to be stuck between 4-6 bars I have not seen green or pink for a while. Normal commute for me is about 75 miles a day, 90% freeway. But being in Los Angeles, some stop and go traffic are involved, which normally adds to the MPG due to more gliding. I have Michelin tires with max psi of 44, set at 43 front and 41 rear. I also have standing order with the dealer to only put in 3.5 quarts of oil because they used to overfill the first couple of time and after I got fed up and made them take some out, they setup in their computer system so it prints a x____ for the foreman to check and sign before returning the car to me. However, I will double check tomorrow morning then report back. as for what other things they did, it was a standard 5K service + cabin air filter + throttle body chamber cleaning. the only thing i've never had done before is the throttle cleaning. on the service sheet, it states "added fuel additive to fuel tank" but considering I'm on my 3rd tank of gas after the service, there are probably non left in the bladder anymore.

    TonyPSchaefer: Thanks for the welcome. =) To be honest with you, I've lurked for a long while and learned A LOT from these forums. I actually don't mind taking it to another dealer as there is one closer to my house than the one I normally go to. But I don't know how to describe my current problem other than lost of MPG. This is part of the reason I really need everyone's help to diagnose this so the dealership can take me more seriously.

    Richard Schumacher: during the 92,000 miles, I've seen the ICE charging the battery and driving the wheel, but I don't recall seeing the electric motor charging the battery and driving the wheel at the same time. I may be wrong, but my understanding is that the battery is the source of power for the electric motor and therefore is yellow arrows flowing from the battery to the electric motor, then to the wheel, or green arrows flowing from the wheel to the electric motor, to the battery during regin. As previously mentioned, there are many times when the ICE is driving the wheel (red arrow to the wheel) and charging the battery (red arrow from ICE to the electric motor and green arrow from electric motor to the battery).

    During my evening commute today, I've even noticed times when it showed ICE to wheel and ICE to electric motor (red arrows), electric motor to wheel (yellow arrow), but no arrows to or from the battery. If my understanding is correct that electric motor is driven by the battery and not the ICE, the yellow arrows should not have been flowing if there are nothing from the battery.

    As for the damaged mass airflow sensor, how can I tell and what should I say when I bring it to another dealer?

    hobbit: thank you, I will call them to find out about if they've dismounted the throttle body but please let me know what is a "TPS". Thanks!!

    Thanks to everyone for the reply. Please help let me know if anything else you can think of before I bring it to another dealer. Thanks!
     
  8. donl73

    donl73 New Member

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    efusco: forgot to add that i've put on about 1000 miles since my initial 8/2 service. as for determining fuel economy, i keep a modified john1701a excel file and have logged every tank since i purchased my '05 with 6 miles on the ODO. during these past few days, temp is about 105-110'F in los angeles and i'm showing 45 MPG for current tank on the display, after putting up significant effort to glide (without much result) and following semis. prior to the 8/2 service, the MPG would easily be in the 53-58 MPG during this type of weather when i put up effort to conserve fuel.
     
  9. efusco

    efusco Moderator Emeritus
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    OK.
     
  10. Mike Dimmick

    Mike Dimmick Active Member

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    TPS = Throttle Position Sensor. A sensor that reports back to the computer what position the throttle blade is in, to confirm that the motor has opened the throttle to the correct angle.

    If the sensor is misaligned relative to the blade, the throttle may be further open than the computer actually asked for, but I would think that in this case that the engine would accelerate and the computer would ask to close the throttle a bit.

    I also found an interesting note in the 2006-2009 service manual, under ECM Power Source Circuit:

    "When the power switch is turned OFF, the ECM keeps the EFI M relay ON for a maximum of 2 seconds, in order to initialize the throttle valve."

    My interpretation of that sentence is that the throttle motor has been switched off and so the blade should be resting against the hard close stop; it reads the position sensor's value in this state and learns the 'fully closed' value for the position sensor. The manual says that the 'off' position should be between 10% and 24% of the full-range value. In Hobbit's experiment, he found that for this throttle body, the 'off' position was 14%.

    First general question: what's the state of your 12V battery? A near-dead one acts as a severe load on the electrical system - like running your bath without the plug in - and causes all manner of problems.
     
  11. donl73

    donl73 New Member

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    i did some youtubing this morning and found several clips of energy monitor for '06 and later models showing arrow behaviors as i've described so i may be wrong on thinking this is a part of the problem. however, honestly don't remember seeing this type of behaviors before. i'll change the topic of the thread.

    regardless, my main concern is not about the MFD, but about the suddent lowering of MPG and possible additional wear on the ICE.

    I've check the oil level and found it within the two dots. called the dealer and am waiting for someone to call be back regarding if the throttle body was dismounted during cleaning.

    Mike: regarding the 12v, checked this morning after car has been sitting in the driveway for about 12-14 hours indicates 9.6v. will now go drive around for 30 minutes to ensure full charge before checking again and report back.

    thanks everyone!
     
  12. donl73

    donl73 New Member

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    sorry, quick search in faq didn't find instructions on how to change the title of the thread... will try looking for it again after checking out the v12 battery charge.
     
  13. Rokeby

    Rokeby Member

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    don|73,

    I think you've nailed it. :cheer2:

    After an overnight rest, the 12v battery should be reading in the low to
    mid 12's. You're battery is definitely no good. This is causing the ICE to
    run overly much to keep the HV battery charged. In turn the HV battery
    feeds the DC to DC converter which supplies 12v to operate the
    computers and alll the other non-propulsion related equipment in the
    car.

    Just for the record, how and where did you get the voltage reading?

    Actually, I'm surprised that your car even starts. It has been reported
    here that 10.5v is the minimum required for the computers to
    boot which is mandatory for the HV battery to be accessed.

    Aren't you the lucky one! :rockon:
     
  14. donl73

    donl73 New Member

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    Rokeby: thanks for the reply! I checked the 12v battery status using instructions found here --> http://priuschat.com/forums/gen-ii-prius-technical-discussion/39798-12v-battery-status.html

    I took the car out for a spin. My house is about 0.4 miles from the freeway entrance, drove 15 minutes at around 63 MPH, got off the free way, then drove back home going the other direction on the same freeway. Outside temperature is about 108’F, A/C set at 68’F with “LO” fan. The trip total distance was 35 miles.


    Time HV battery SOC
    1:05pm 5 bars
    1:08pm 4 bars – got on freeway
    1:10pm 5 bars
    1:14pm 6 bars
    1:23pm 7 bars – during freeway exit, breaking appears to have increased regin
    1:24pm 7 bars – got on freeway going other direction
    1:28pm 6 bars
    1:36pm 6 bars – started following semi and slight down hill
    1:39pm 7 bars
    1:41pm 7 bars – exit freeway
    1:43pm 6 bars – arrived home

    It took nearly 15 minutes of freeway driving to charge the HV battery from 4 to 7 bars on the way out. Also during the drive, I’ve noticed that car started behaving normally after the HV battery reached 7 bars (green) at 1:23pm. On the way back, noticed loss of power at 1:28 after SOC went down to 6 bars. At 1:41, after exit of freeway with 7 bars, was able to glide the whole 0.4 mile back to my house, even after coming to a complete stop at the freeway exit traffic light.

    Parked in the drive way, and checked 12v status after shutting down. 12v battery showed 12.2. Turned on the head light dropped it down to 9.0v, turning off the head light and saw it raised back up to 10.2.

    After seeing what Rokeby wrote, it sounds like the 12v battery. Called both dealership for price quote. The original dealership which did the 8/2 service asked for $174.76 on parts + $85 labor. The other dealership’s service department was closed for the weekend.

    Here comes the next question. Should I get this fixed at the dealership immediately? Or should I order the Optima unit from eLearnAid and wait for it to arrive before swapping it out? Considering I will be going on an 8 days business trip on 9/2 so the car will probably just sit in the drive way during the trip. I have Nav and smart key.

    Also, I’ve read through hobbit’s very impressive battery guide and have one question regarding floating the ancillary 12v battery. Can I just hook the jump point up with another car using jumper cables to avoid loosing settings?

    Thanks!!
     
  15. Rokeby

    Rokeby Member

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    Don|73,

    you are most welcome for any help I've provided. That's what PRIUSchat
    is all about.

    It is clear from the references in your last post that you've been doing
    your homework. Well done. At this time, you may in fact know as
    much as I do about diagnosing and replacing your 12v battery. ;)

    FWIW, I would order the Optima battery immediately, they have a
    reputation for very fast service. (Don't forget to get the Prius specific
    adapter kit. IIRC, it goes for about $15.) Also, I recommend that you
    disconnect the 12v battery while you're away. It can't do any good,
    and in it's current state it may do some real harm.

    One last thing, no matter which battery you go with, OEM or Optima,
    ensure that it is fully charged before you install it. If it is only partially
    charged, in a short time you will see this problem again.

    You don't say in your avatar what model year Prius you drive. My
    experience is that at least for my '08, I didn't loose any settings on the
    two brief occasions that I intentionally disconnected the 12v battery.

    At this point, I'm going to pull back for some time with the hope that
    more knowledgeable posters will come up and answer your question
    about floating the battery... 'cause I don't know from nothing'. :p
     
  16. vertex

    vertex Active Member

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    You definitely need a new battery. I doubt that your car will start when you return from your trip without changing it first, or jumping it. Battery replacement is easy to do. You have at least 3 options, OEM replacement, OPtima or Exide. Optima is the best choice if cost is no object. I recently changed mine with the Exide, you can find the post here:
    http://priuschat.com/forums/gen-ii-...66601-battery-replacement-economy-method.html
     
  17. donee

    donee New Member

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    Hi Donl73,

    To be concise but reiterating Vertex's comment - You definately need a 12 V battery.

    The hybrid system SOC's you gave look to be perfectly normal to me.

    As too your picture, after the initial start, I actually trim my peddle postion to get exactly that display for a while. Nothing wrong regarding it at all. Once I get closer to speed the battery charging arrow comes on, and the loop (electric torque-converter) mode will stop.

    Evan et al moderators, I did not doubt for a minute Donl73 was noticing something different. He just was not communicating anything out of the ordinary, initially. He had to work harder for us to help him. Now he has, and hopefully all will be fine.
     
  18. donl73

    donl73 New Member

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    Vertex: thanks for the suggestion on the Exide model. In the end I decided to go with the Optima consider it was cheaper than what the dealership wanted to charge me for the OEM, before labor charges.

    Donee: thanks for your reply, its all good. After your message I did some youtubing and discovered it seems very common for '06/after models. Perhaps it is also common for '05/before models but I honestly don't recall seeing it before. However, it probably isn't part of the problem so I'm now not very concerned about the display anymore. Besides, I'm not the type who throw out a question, then expect "hand holding" from there on, so I totally expected to put up effort on my end when asking for help. =)

    At any rate, a BIG thank you for everyone who have put in suggestions. I've ordered the Optima + kit for total of $163-$25 MIR, w/free shipping. Will work in this direction and report back regardless if it solves the problem or not.

    One last thing, I'm still interested to learn about floating the ancillary 12v battery, thanks!!

    -don
     
  19. donl73

    donl73 New Member

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    I came back from my biz trip on Thursday and somewhat to my surprise, car started fine. Replaced the 12v battery today, which was relatively easy. No corrosion on the terminals of old battery. But unfortunately it doesn't appear to have solved the problem.

    Something I want to add to how I feel when driving, and things I've notice is different compare to pre-service. It feels like the ICE is almost always trying to charge the HV battery and therefore I'm not getting any power assist from the electric side. Car starts to feel normal once the SOC gets to 7 bars (green) and I can glide without much effort. On the few occasions it got into the greens, it took a long down hill or downhill freeway exit to get there. On most drives it never gets to 7 bars but instead stays at 6 bars for the whole 20-40 minute drive, rarely going below 6 bars and never getting to 7 bars.

    It now doesn't feel like the TPS. Would MAS have this type of effect? Or is it the HV battery? I'm really hoping IF it’s the HV battery, I have it figured out before the extended warranty expires. Please help suggest what I should do next. Thanks!!
     
  20. northwichita

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    Or is it the HV battery? I'm really hoping IF it’s the HV battery, I have it figured out before the extended warranty expires. Please help suggest what I should do next. Thanks!![/quote]

    Track daily mpg, a noticeable decrease would be a good reason to have the HV battery checked by the dealership.

    About watching of the battery bars of charge, I've found from experience I get the highest charge reading on the second trip of the day, which starts an hour after my commute. I drive the same places (delivering mail) and consistently about 15 minutes from startup into a section of boxes I've noticed the highest battery reading, green bars, one from the top. From then on it goes down to around 6-7 bars for the day.

    Buying a scanguage and programming it with the extra codes lets a dyier check the status of the HV battery, the state of charge difference (csd) is said to be the best indicator of battery health. I figured this out last weekend , and mine (an 04 with 155k +) read at 0.0%. Made me very happy.

    Arts garage writeup on this
    http://www.artsautomotive.com/hybri...battery-failure-analysis-for-the-prius-hybrid
     
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