Check engine light with low (but not empty) gas tank?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jgrn307, May 9, 2009.

  1. jgrn307

    jgrn307 New Member

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    So the last two fillups on my 2009 Prius (only 3500 miles, the car is nearly brand new) I have had a situation where about 30-40 miles after the car says to fill up, I get the check engine lights all coming on. Both times after I filled up with gas, the lights all went off. The second time I was on the highway and noticed that the gas engine has shut off (at 70mph) and I coasted in on battery power to a gas station. The first time I was in the city, so I may not have noticed if the gas engine has shut off.

    Here's the weird thing -- in BOTH situations this occurred only 20-40 miles after the gas warning came on, and in BOTH situations I only needed to put in approximately 9.5 gallons of gas in the car, so this meant I still had a gallon and a half left in the tank at the time of fillup! Why is my car shutting off when I clearly have gas left?

    The gas cap was on securely, so that's not an issue. Time for my first warranty repair?
     
  2. firepa63

    firepa63 Former Prius Owner

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    You ran out of gas. The "guess gauge" in the Prius is not the most accurate of gauges. The bladder in the fuel tank expands and contracts with temperature which compounds the inaccuracy. I suggest that you fill up when you get down to 2 pips. Running out of gas can shorten the life of the traction battery.
     
  3. JimboK

    JimboK One owner, low mileage

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    Actually, when it flashes it is pretty accurate. It means if you don't get gas now you'll soon run out of fuel.

    So Jgrn307, I agree; you ran out of fuel. Though one could make an argument that the fuel bladder design leaves something to be desired (presumably why Toyota left it off the 2010), this is not a defect to be fixed under warranty.

    Do a good search here to find out more. There are dozens of discussions on this.
     
  4. Jared

    Jared Member

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    I have often gone 40 miles after the blinking starts and never run out of gas.
     
  5. CharlesJ

    CharlesJ Member

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    The book and Toyota fuel tank capacity is 11.9 gal so you should have had about 2.4 gal left.
     
  6. firepa63

    firepa63 Former Prius Owner

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    Jared & CharlesJ, as I said, it's a 'guess gauge'. With the bladder you cannot accurately calculate the amount of fuel left in the tank when the last pip starts flashing, nor can you calculate how much fuel you can actually put in each time you gas up. There are tons of post about this subject here on PC.
     
  7. Tammy7287

    Tammy7287 Junior Member

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    My question is....why would you wait until 30-40 miles AFTER the gauge says you need gas to actually GET gas? That's just pressing your luck if you ask me.
     
  8. patsparks

    patsparks An Aussie perspective

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    Does anyone read the handbook which is in the glove box?
    Like all cars it says in the handbook "It is a good idea to keep at least 1/4 of a tank of gas in the gas tank" or words to that affect.
    I fill with 2 bars on the gas gauge and still manage to get 50% further on a tank than I did in my Camry.
     
  9. richard schumacher

    richard schumacher shortbus driver

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    No, sorry. This is another apparent error in the US owner's manual. If the bladder were removed from the tank, the tank might hold 11.9 gallons, but as it is you're lucky if the bladder holds nine gallons.

    Anyone who habitually drives after the gas gauge starts to flash will run out of gas sooner or later. It's just a bad idea.
     
  10. stevemcelroy

    stevemcelroy Active Member

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    There are a number of folks who seem to really stretch the distance that they go on a tank - I guess that I do not get it - what's the big deal with stopping for gas before you are running on fumes? A stop at the gas station takes 5, maybe 10 minutes.

    I'm actually the opposite - my first car was an old Volvo with a weak fuel pump - if it fell below about 1/3 of a tank the car would shake and buck like crazy - I drove it for 6 or 7 years like this. It has been 15 years or so, but I still find it hard to let the tank get below about 1/4 full.
     
  11. jgrn307

    jgrn307 New Member

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    The second time I was in an area where there aren't a lot of gas stations, with a dog in the car who has less-than-perfect bladder control. The *dealer* told me I had about 100 miles before I ran out of gas. This, combined with the notion that the manual says I have 10.9 gallons and that the warning comes on when there is 2 gallons of gas left (80+ miles given how I drive), and that when I filled up I only put 9.5 gallons in it, but I have filled up with *10.5* gallons before, having driven approximately 30-40 miles after the last pip, and didn't have the car switch into battery mode. I'm not convinced I just ran out of gas, unless the gas tank changes how much it can *hold* over time.

    I'll check the other forums, but I am taking the car into the dealer to have it checked out, I'll let you all know what they find (if anything).
     
  12. edthefox5

    edthefox5 Senior Member

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    Yes you ran out of gas. More than once apparently. And as usual the dealer 100 mile info is wrong. Really stupid wrong. I assume a salesman? In the future try not to listen to anything the dealer says for the most part.

    Try to save some time and aggravation and pick up a Scangauge right here at Priuschat's Shop. Its the orange SHOP button on the top of the page here. We all have one and there really handy and not only can you get alot better mileage with the info it provides its also an OBD II Code reader and can pull the codes your car has thrown at a push of a button. And btw when you take your car into the dealer he will read those same codes. Only it will take you a couple of hours of sitting around to get it from them. If it was me I would want to know exactly what my car is complaining about before I take it to the dealer.

    I would be hesitant to allow the dealer to see I ran out of gas. They will be able to tell instantly by what code has been thrown. Who knows in the future if something fails they could say you ran it out of gas...continued to drive.....stressed out the electric motor and the main hybrid battery {which you did because thats what you used to limp to the gas station with} and caused damage to those circuits.

    Times are tough at the dealer.They need cash.Who knows how stupid your dealer can get over this. At the very least a service ticket is created and stored there.

    This car's Hybrid System is not designed so you can drive miles and miles to get you to the gas station when you run out of gas with all the CEL lights on. Lots of horror stories here about that very scenario. I remember distinctly one guy posting complaining the car wouldn't get over 70 miles an hour in that electric only dead engine mode. I think he damaged the electric motor also. Madness.

    Its designed to get you off the road 100 feet so you can call a tow truck.

    One thing you must know about this car. If it throws a check engine light do not drive it until you find out what its unhappy about because you can really f**k this car up driving with CEL lights on.

    Lights on and it ain't kidding.

    Good luck.
     
  13. jayman

    jayman Senior Member

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    What is it with running a car on fumes? I get nervous when the tank gets to 1/2. Up here it can be a survival issue, especially at -40 with windchills of -60

    Some folks claim no harm is done by consistently running a tank at 1/4. The electric fuel pump lives in the gas tank, it is cooled and lubricated by the fuel. Run it dry too often, and you f*** up the fuel pump

    Yes, codes are stored when the tank runs dry and the engine quits. Ruin a traction battery, inverter, M/G, etc by pushing on, don't expect any sympathy
     
  14. richard schumacher

    richard schumacher shortbus driver

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    Now where does the manual state that there are two gallons left when the gauge starts to flash? OTOH the 2004 manual states on p.114 "Depending on the ambient temperature the fuel quantity is less than [11.9 gallons] even at 'F'."

    The dealer will find nothing wrong, although they may not say that because dealers are in the habit of making up sh!t on the spot to make customers calm down and go away. You ran out of gas. Driving on battery alone after running out of gas can reduce battery life because it will discharge far deeper than it was designed to.
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This does sound like a running-out-of-gas incident. If the dealer tech retrieves the logged diagnostic trouble codes, it is likely that s/he will retrieve DTC P3193 "Fuel Run Out".

    I recommend that the OP consider the fuel tank capacity to only be 9.5 gallons, to minimize the likelihood of a repeat incident.
     
  16. Politburo

    Politburo Active Member

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    2009, pg. 426. It actually says that the flashing pip means three gallons (or less) is in the tank. When I read that, I was pretty sure it wasn't right. Then I read about the fuel bladder issues here, and knew for sure that it wasn't correct.
     
  17. F8L

    F8L Protecting Habitat & AG Lands

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    I suggest the OP take the advice given in this thread. There are a lot of very Prius knowledgeable people on this forum and over the years we've learned a lot about the Prius fuel system and other components. It's better as a new Prius owner to not assume you know anything about the car and just listen to these guys first. In many cases they do know more than the average dealership salesman AND a lot of the mechanics too. :)

    FWIW, I've never fit more than 9.3ga in my Prius and that was with the last PIP flashing and 80+deg temps. I usually fill up when I get down to 2 PIPs.
     
  18. richard schumacher

    richard schumacher shortbus driver

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    The "(or less)" is the key part. There's no guarantee that any particular amount is still available.

    I agree that the owner's manual is not a model of clarity. Toyota ought to hire whomever writes the Honda owner's manuals.
     
  19. richard schumacher

    richard schumacher shortbus driver

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    Yes; I had the impression that the OP had cycled the car enough times to clear all codes (or is that one "sticky"?).
     
  20. Matt Herring

    Matt Herring New Member

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    A Scanguage II is a great suggestion, I have one, and the benefits of reading your own codes is a great one. However, before we send this guy out to buy a SGII it should be noted "The Scanguage is not an accurate measure of how much gas you have left in the tank...DO NOT use it to accurately meausre how many miles you can drive on the ramaining fuel in the tank...even if it says you can drive x number of miles on the remaining fuel!!!"

    Especially with the Prius, the SGII is WAAAAAY off on miles to drive and gallons of fuel left...just thought that needed to be said in this thread.
     
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