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Hello! I'm new to the forum, and new to being a Malibu Hybrid owner. I purchased my 2016 Hybrid a few weeks ago and everything was good - until...

1. I had my tires rotated and the shop used an OBDII TPMS scan tool to reset the placement of the sensors.
The car had to be running for the scan tool to work. As soon as it was done and the car was restarted, the check engine light came on with a Hybrid System code (which we cleared and everything was good after that).

2. A few days ago, I stopped for gas (the gauge was at 3/4 of a tank but I wanted to top off). In a 13 gallon tank, I wasn't expecting to pump 9.85 gallons of fuel to fill up.

3. I then drove 220 miles, and the fuel tank still registered all the way full. The MTE display went from 460 after fill up to 439 when I got home (after 220 miles).

4. Yesterday, when I got in the car, the fuel gauge registered completely empty and the MTE showed two dashes (-- miles to empty). I had driven 220 miles from filling the car, so I knew it was wrong. I turned off the car after driving about 10 miles, gunned it from a stop when the light turned green, and suddenly the gauge went back to completely full (with 419 miles to empty).

I drove about 25 miles and the gauge didn't move, but the MTE display went down to 412.

Of course, my car is a 2016 with 41k on it, so it's out of bumper-to-bumper warranty. I called the dealership and they want $120 to diagnose the issue. My husband is a technician at NTB, but they can't work on Hybrids (other than basic maintenance).

I called Chevrolet Customer Service and they told me that I'm basically SOL because it's out of warranty, and that there were no TSBs or recalls on that issue.

Has anyone had this issue before? What could cause this? I drive 1,500 miles per week for work (which is why I chose this car), but don't feel comfortable if I don't know how much fuel I have...

Any help or direction would he greatly appreciated!!!!

Thanks
Stephen
 

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Post approved. I'm not sure why it required approval but you got it.

I have read another hybrid owner mention extreme overfill in the tank also. The reality is these tanks are much bigger than they are designed to fill (the real volume is 16-18 gallons). For whatever reason, at some point something is malfunctioning (or at least not working as intended) and allowing more fill. It seems yours went to something around 17 gallons. However, you report a lot more consequences and/other malfunctions. I will tag that other user so perhaps he will notice and share his experience. I don't think he had any problems though but worth a try.

Hello @Dr. Manhattan!
 
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Hello! I'm new to the forum, and new to being a Malibu Hybrid owner. I purchased my 2016 Hybrid a few weeks ago and everything was good - until...

[/QUOT
Sounds like you might have a bad fuel level sensor inside the tank as I did. Symptoms are different, but sounds similar. Mine was under warranty so I'm not sure what it will cost to fix.

 

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Sounds like you might have a bad fuel level sensor inside the tank as I did. Symptoms are different, but sounds similar. Mine was under warranty so I'm not sure what it will cost to fix.

I don't recall the exact code that triggered the CEL, but on the Solus I remember it said "Hybrid Drive" something or other. It did not mention fuel or anything like that.

As of today, my gauge went down a bit but I still don't think it's correct. Do you recommend trying to refuel at a certain milage (like after 400 miles or something)? I'm hoping it was just a fluke, but I'm worried nonetheless.
 

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When OnStar diagnosed the problem, they gave me a vague generalization about the hybrid drivetrain (two scary words) isn't performing optimally due to fuel delivery or something to that effect. Advance Auto gave me the intermittent fuel level sensor reading when they read my code. Mine seemed to have a problem when near 3/4 to full. When near a half a tank it seemed to be close to normal. But the CEL never went out on mine until the dealer repaired it. There are probably 3 connections to the sensor. I think the symptoms might vary depending upon how the sensor is failing. They will also check to make sure the wiring to the sensor is OK before they replace it. I think they pulled the rear seat to gain access. The repair went too quickly to have required dropping the gas tank in my opinion. I doubt it's a fluke. Mine seemed to be a fluke until several months later the CEL was set. The gauge never went to zero in my case and actually appeared to work fairly accurately before the repair.
 

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Do you know if they considered it part of the drivetrain, or how the dealer wrote up the repair? I have some aftermarket warranty that the dealer sold me that covers certain things.
 

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Can your husband get the wiring diagram for the car. I feel like campb292 it is the sending unit on the side of the pump in the tank. It should be an arm with little fingers at the turning point of the arm these run a semi circle of traces. ( flat metal ). But before I would be a parts changer I would go through the wiring diagram. You should find the volts and amps and resistance.and you will need them if you have to remove the battery if you can’t get them or money is tight go to the Library on their computers and use Mitchell pro. To look up all procedures on how to diagnose and remove anything in the way.when he is sure what part is bad. Mitchell also has a diy that is at a reasonable cost. For your own computer.but wiring diagram will be better at the library. Good luck and let us know how it turns out. Buy only gm parts it will cut down on Failures. Amazon and Rock auto. Is a good place to buy parts. Besides the dealer. Prices can very widely.make sure to get all parts needed if you open up the tank.
 

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Can your husband get the wiring diagram for the car. I feel like campb292 it is the sending unit on the side of the pump in the tank.
Remember that you are working around very dangerous fuel vapors if you open the tank. A do it your self repair could be catastrophic if you're not careful. Very easy to generate static electricity sparks in the dry winter months.
 

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And doing DIY electrical on a Hybrid is another animal. The warnings and procedures in the service manual are BOLD and frequent. There are lengthy steps for disabling and discharging the HVB. You don't just get shocked your fingernails and eyes might melt (haha).
 

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Follow Mitchell pro guild lines. Safey is number one Mitchell pro. If you can’t follow along and understand Mitchell pro guild lines, PPE, direction, and tools needed to do the job, take it in for service. Again you can get Mitchell pro on the Library computers.
 

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Sorry I haven't checked in in awhile. The OP should be made aware that the "12.8 gallon" tanks on the early (his '16, my '17, and maybe even the '18s) MH's are, in fact, the same "15.8 gallon" tanks as every other Malibu got. And, that the capacity difference was actually in the filler neck venting, which on the MH and 1.5L were designed to cause the tank fuel to puke back and shut off the nozzle at the 13 gallon mark. What the OP found, apparently by accident, was that if certain airflow/venting conditions occur within the filler neck during refueling, the fuel fails to puke back and shut off the nozzle and the nozzle continues to flow until the tank is actually full. Since the OP's fuel gauge is calibrated to the 12.8-gallon value, his gage continued to read full for his first couple of hundred miles. This is normal when the tank is actually full.

What is not normal is that something in his gage or sender circuit is also intermittantly failing, which is an entirely separate issue.

When I'm out on extended road trips, I intentionally "over" fill my MH's tank, and as a result I usually see about 700 miles between gas stops. The gage typically doesn't move off of the "full" peg until around 230-240 miles. As near as I can figure on what I've seen so far, the true ultimate capacity of our Malibu tanks is something close to 18.5 gallons, but keep in mind that that's with zero air space left in the tank/system...which allows zero room for the expansion of potentially warming/expanding fuel! So, don't be parking your car anywhere, anytime, with the tank in this condition. That situation would be fraught with negative possibilities ?, so unless you're filling up to immediately continue a road trip...don't do it. That's my advice, anyway...
 
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