REX Refueling / Check Engine Light / Fuel Tank And Emissions System Damage

[user 8033]

I haven't ran across an in depth explanation of what occurred with refueling and the fuel tank with my 2020 i3, so I thought it might be helpful to share my experience to warn others.

When I took delivery of the i3, the salesman didn't give any kind of warnings about filling the REX fuel tank. And with winter approaching and no need for the REX to run due our limited travel range, I thought I'd fill the fuel tank and be done with it. So I did just that, filled the fuel tank. And not to the point where it was running out. Likewise, I didn't raise the fuel pump higher in the fuel neck to get the last drops in, etc. This was in November 2020.

Four months down the road, the REX had succesfully ran twice for maintenance. After the second maintenance phase run, the REX triggered a check engine light. When it didn't go off, we took the i3 to a dealer.

The dealer then told us the car had $1,800 in damage to the emission system from the fuel tank being overfilled. And they wanted us to pay for it, claiming it's not a warranty repair.

I did a Google search on the topic while they had the car and while waiting to see if this would get paid for. I only found one other person in a similar situation. They claimed they had a similar problem four times and each time BMW fixed the car for free. The person said the BMW dealership repeatedly accused them of overfilling the fuel tank. They denied doing so.

A search of the i3 manual doesn't shed adequate light about what occurred. For example, an i3 manual at i3guide dot com states the following: " "Do not overfill the fuel tank; otherwise fuel may eslide, causing harm to the environment and damaging the vehicle." Observe the manual doesn't warn about damage to the emissions system by merely filling the fuel tank.

Reading that excerpt, in my opinion, from the manual doesn't warn you that merely filling the fuel tank on this car can translate into an $1,800 repair bill and the REX being disabled. To me, it comes off as more of a warning about damaging the paint and the environment.

The owner's manual for my car isn't much better at BMW's website. First it reads "Fuels are toxic and aggressive. Overfilling of the fuel tank can damage the fuel system. Painted surfaces may be damaged by contact with fuel. Escaping fuel can harm the environment. There is a risk of damage to property. Avoid overfilling."

But then manual contradicts itself. First saying this: "The fuel tank is full when the filler nozzle clicks off the first time." And then saying this under emergency refueling it says: "Refuel the vehicle as usual. The excess pressure in the tank may make refueling difficult, for instance the fuel pump nozzle may shut off frequently."

So if the fuel pump nozzle is "shutting off frequently," you wouldn't be advised to stop with the first click off, would you while performing a fueling after opening the fuel tank when the button didn't work and you had to do it from inside the front trunk. Which would then potentially result in an $1800 repair to the emission system: a charcoal canister, lines and a sensor. A crazy amount of money for those items in my opinion about that too.

Likewise, setting the fuel nozzle to auto run and it not cutting off and the result of that adding to much fuel could theoretically trigger this kind of repair too.

Just wanted to warn all of you to be very careful when refueling this car. I'm almost scared to put fuel in this silly thing anymore after this incident. I'll certainly be adding far less than two gallons just to be precautionary from here forward.

After some arguing, BMW agreed to fix the car "one time" as a "goodwill" repair, but they initially insisted that we pay for the damage.

Cars should be built as dummy proof as possible in my opinion, but not the case with this i3 if you can do so much damage by merely filling the fuel tank.

This is priceless in the manual too: "With a driving range of less than 30 miles/50 km the engine may no longer have sufficient fuel. Engine functions are not ensured anymore. There is a risk of damage to property. Refuel promptly."

So you're screwed either way. Too little fuel, or too much fuel apparently cause damage.

 

[Deutsch100]

THIS was me with the problem. 4 times with my 2019 i3S Rex. After 4 times fixing the check engine light and a saturated charcoal canister...BMWNA bought my car back. I have had my 2020 i3S Rex now for 7 months and zero problems.

The second time they accused me of overfilling the tank, I filed a complaint with BMWNA. Not only did I not fill the tank, the gas level was the same for several repairs. They never once said I had to pay for repairs, but I did not appreciate them saying I caused the CEL.

 

[Thomasi3]

I have a 2020 i3s 7300 miles and I brought it into the dealer for yearly maintenance I sought the engine light came on for that but was told I overfilled the tank and it will cost 1650 $ to repair . It is Bob Smith BMW in Calabasas CA..I told them I only filled the tank twice and the light came on. Probably 4 month after I filled the tank. They kept on insisting it’s me who made the mistake . It’s my 4th i3 and never had that problem . Is this a problem with the newer I3s ? It’s my first s.
Can it be fixed by yourselves ?
After seeing your comments I will try to fight it . After 46 years driving I never had a problem overfilling a tank this is real outrageous I think this will be be my last BMW there arrogance is just intolerable .

 

[Anonymous]

I think this will be be my last BMW there arrogance is just intolerable .

You may be misplacing your wrath. BMW Dealers are independent entities running a franchise. Some are great. Some not so much. I have four BMW Dealers in my area. Two of them I wouldn't take my i3 in for service if they paid me to. One so bad you are almost guaranteed they will try and make you pay for unnecessary 'phantom' repairs. In some dealerships the service area is run as a separate business, where the techs and service writer are all independent contractors who get paid a percentage of each job, so the more high-dollar repairs they can book, the more money they make - and those shops are notorious for scamming the customers to boost profits, and hate doing warranty repairs as it can take 30 to 60 days for BMW to pay them for the work. My advice would be to go to another BMW Dealer in your area (check Google and Yelp reviews first) and get a second opinion. And let them know up front that there is no way that an 'overfill' error suddenly shows up four months after the last fill, as the previous diagnosis will be in BMWs service records. If you still get the runaround - Call BMW USA and complain that the dealer is refusing to do warranty work on the car, and ask that their regional Dealer service liaison get involved - because I am sure I have seen posts from people with cars still under warranty who DID overfill, immediately got the engine light and had the problem fixed under warranty, with a warning not to let it happen again. To flood the emissions system with gas, you really have to work at it by clicking the fill leaver on the pump handle several times to keep gas flowing into the system until it overflows the systeme. I've seen people at the pump clicking the lever a half dozen or more times until gas is running down the side of the car, to get that last drop in - and that's almost but not quite what it takes to overwhelm the i3 carbon canister too, otherwise we'd have a whole category just to hold the thousands of messages on having to 'fix' i3 REx overfills. This BMW Dealer KNOWS this, but it is an easy repair add-on scam for dishonest repair shops, as how do you prove you didn't overfill the car?

 

[Deutsch100]

I have a 2020 i3s 7300 miles and I brought it into the dealer for yearly maintenance I sought the engine light came on for that but was told I overfilled the tank and it will cost 1650 $ to repair . It is Bob Smith BMW in Calabasas CA..I told them I only filled the tank twice and the light came on. Probably 4 month after I filled the tank. They kept on insisting it’s me who made the mistake . It’s my 4th i3 and never had that problem . Is this a problem with the newer I3s ? It’s my first s.
Can it be fixed by yourselves ?
After seeing your comments I will try to fight it . After 46 years driving I never had a problem overfilling a tank this is real outrageous I think this will be be my last BMW there arrogance is just intolerable .

I too go to Bob Smith BMW in Calabasas. I wonder if this is now their M.O. or BMW's M.O. to blame the customer now if the Check Engine light comes on with REX? I wonder how common and serious this issue really is with REX equipped i3? I love, love my 2020 i3S Rex, but the Check Engine light that could come on freaks me out almost daily!! Since my 2019 REX was such a nightmare, I still have kind of like ptsd, and EVERY time I turn my i3 on, I wait for the Check Engine light

 

[user 8033]

Good to see people sharing their experiences about the REX overfilled fuel problem in this thread, so others will be able to fight these erroneous and ridiculous repair charges. Hopefully, this thread will start showing up in search engine searches because there's not much information about this issue on the web.

In my opinion, the fuel system on the i3 is improperly designed and the owner's manual doesn't adequately document or warn about the catastrophic damage that can occur when putting gasoline into this vehicle.

My REX came on successfully once since the repair after I discharged the battery past 6-percent.

I'll see how it goes, but I'm definitely not putting more than 1 to 1.5 gallons of fuel in this car when it's empty for the rest of it's days with me.

 

[virtualy]

I've just registered with this forum. I did that so I could post this reply, tagging this thread for others to find.

I bought a 2016 REX just off lease last year, my first BMW. We've enjoyed driving the car, especially past gas stations. I got an engine light a few weeks ago and ran a scan via the OBDII port. The error code was P018B $07E8 (Fuel pressure sensor B circuit range/performance). I later discovered the fuel door would not open. I reluctantly called the local dealer and spoke with a service rep. Sight unseen, he diagnosed the problem - a bad fuel pressure sensor. He said it was a frequently encountered problem. As discussed above, quoted repair cost was $1800. Immediately after I groaned he said it was covered by my warranty. I took the car in and it was repaired and back in my driveway a day later.

Please forgive me if the preceding error code has been posted elsewhere on this forum. I was unable to find it with a search which, again, is why I'm posting this.

Thanks for this discussion.

 

[johnheddy]

I was recently showing a friend my "new to me" 2017 i3 REX and let him drive it and showed him the emissions control test mode... anyway, while playing around, I think we cut off a test in the middle and I got a check engine light.

I bought an OBD2 reader and it called out as an EVAP valve failure "Permanent Diagnostic Trouble Code". And ... it would not clear.

I went online to see how to clear the code but it required a "standard drive cycle" to be run where you idle for 30 seconds, then drive over 40 KPH (25 MPH) for 5 minutes or longer, then idle for 30 seconds and turn the ignition off (all in one ignition cycle). Well, even coded to allow turning the REX on at 75% SOC, you can't make it do that sequence. If you stop, the REX shuts down instead of idling. I tried to meet the criteria and it failed to clear by driving.

So I thought, why not try that sequence with the emissions control test mode. It could meet all the criteria except the over 25 MHP part. That cleared the code and turned off my check engine light.

Here is the sequence I used:
1) pop the hatch (don't need to open it just press the unlock button)
2) foot on accelerator, and NOT on the brake, press start/stop.
3) pump brakes 3 times and hold on last pump (emissions control test message appears, but engine does not start yet)
4) press start/stop button to start the REX engine.
5) foot off the accelerator and brake to put the REX in low idle speed for 30 seconds or more (I did 60 seconds).
6) foot on the accelerator for 5 minutes (I did a bit over 5 minutes).
7) foot off the accelerator for 30 seconds or more (I did 60 seconds).
8) press start/stop twice (maybe 3 seconds apart) to stop REX and put car to sleep.
9) foot on brake, press start/stop to wake up car in READY mode... and see check engine light is now off.

Just wanted to share that as something to try before spending $1800 on a dealer replacing your EVAP system.
It should clear any transient Permanent DTCs. You will need to clear any normal DTCs with a OBD2 scanner.

This does not reset an code if the problem still exists. In order for the code to clear, the problem must not show up during the whole 6 to 10 minutes of run time for the REX. If it shows up, it will not clear. It is handy to be able to weed out transient issues though as opposed to actual problems with the REX.

There was actually nothing wrong with my REX, it just glitched at the wrong time during a diagnostic self test (because we pressed the start/stop button mid test I think). But the check engine light would not go off until I proved the REX was ok by doing a "standard drive cycle" test.

 

[user 8033]

Thanks for sharing those reset steps.

I've decided the best way to resolve my REX worries is get rid of the REX. I hate the effing thing. After that $1,800 stunt with the dealer, it's just anxiety provoking to even put fuel in the thing. Or worry whether the next maintenance cycle is the next check engine light. Or worry that the fuel has gone bad, which is only good for 3-6 months without additives. I'd rather worry about having to run out of battery charge than I would to continue to deal with the thing. My 2021 BEV doesn't have it. My 2020 REX is hitting the road and finding a new owner.

https://www.jdpower.com/cars/shopping-guides/how-long-can-gas-sit-in-a-car-before-it-goes-bad

 

[johnheddy]

I like my REX, especially since the car is coded to let me turn it on at 75% SOC or lower. It is handy if I forget to plug the car in at night. I have a 60 mile round trip to work and back each day, and the 2017 model has around 120 battery only miles on a full charge. It is a bit scary getting up and seeing 45% charge because I forgot to plug in ... OOPS!!! But when that happened, I just burned a 1/4 of my 2.4 gallons of gas to hold that 45% on the drive to work, so I could drive home comfortably on battery. I might have almost got home if I didn't have a REX. There are not so many charging stations around this part of the country. Nearest DC fast charge station is about 90 miles away... so that is no help... there are a few car dealers that provide level2 charging for free on a first come first serve basis, but none that are conveniently placed to my drive home from work.

I wish I had a larger tank on it to allow me to take longer trips without having to wait so long to recharge or stop so often for gas. I would keep the tank mostly empty (maybe a couple gallons) except on a long trip, since day to day driving can be accomplished totally on battery... as long as I don't forget to plug in that is.

 

[johnheddy]

Wow, I just did the math, and if the fuel gage is right, 1/4 of 2.4 gallons is 0.6 gallons, and the trip was 30 miles (2/3 highway). That means the REX had a net fuel economy of 50 MPG while holding the same state of charge I had when I left the house. That seems high for a series hybrid design so I am questioning the fuel gage, but this may be a clue as to why BMW does not really want to use the REX to charge the battery.

Energy is lost when charging a battery, and more is lost when discharging the battery and using it to drive an electric motor. If the power from the REX is applied to the motor and either the battery or a capacitor bank is used to smooth out power usage spikes, you avoid the efficiency hits of charging and discharging the battery. Capacitor banks are far more efficient at charge and discharge cycles than most batteries, but don't have the energy density needed for long term storage.

I still would like to have the option to do some charging of the battery, at least to 75% charge on demand, and a larger fuel tank. That would allow usage of the i3 as a plug in hybrid car on long trips (300 to 3000 miles) where there is not enough time to stop and recharge every 1.5 hours for half an hour.