My new M4 has a bad O2 sensor after just 480 miles

[MLAW702]

I was very excited to become an M4 owner after waiting so long to finally be able to afford one.

Last week I pulled the trigger on a 2017 M4 Black Sapphire with Carbonstructure interior. After only 100 miles the drivetrain malfunction light came on and the car went into limp mode. The car reset after shutting off, but the check engine light remains on. Though the drivetrain malfunction light is gone. I took it to the dealer the next morning. They read the codes and blamed it on bad gas.

After much thought and some online research it appeared this could be the issue so I gave them the chance and topped it off with more 91 octane. The light has been on and off all week after several fill ups at different gas stations. I took it in to BMW yesterday and waited for three hours for them to tell me its a bad NOx/O2 sensor by the intercooler and he cant see if its loose cause the car it too hot. Bank one read higher than bank two (whatever that means) so they ordered a new sensor and will need the car a full day to replace. Hopefully this solves my issues. Very frustrating buying a brand new car when I can't drive it and break it in properly.

[E90Fleet]

Sorry to hear. Things like this are never nice, but hopefully its just a faulty small cheap part.

Hope its 100% soon.

These things happen.

[Alpine300zhp]

Originally Posted by E90Fleet

Sorry to hear. Things like this are never nice, but hopefully its just a faulty small cheap part.

Hope its 100% soon.

These things happen.

Agreed. If the part failed that quickly then it was a bad part at assembly time. I wouldn't worry about it since it is an easy fix and most likely an anomaly.

[MLAW702]

car has not thrown any codes the last 2 days (90) miles of driving. Sometimes getting on it would throw the cel light. Now im confused the car was having the light come on every drive. Goes into the dealer tomorrow

[bb1857]

My guess is bad gas and not a faulty sensor. I am bit confused as to how you have had "multiple" fill ups within 480 miles of driving though. Even getting shitty mileage I can go 300 miles on a single tank so my guess is that you got a bad batch of gas and its still in the system. If it was bad enough to throw a code it will have to empty from the system completely. If you have been "filling" up with a couple gallons here and there you are just diluting the bad gas, not removing it. I'd let it run down to empty and fill it back up with a quality gas, run that near dry again and see if any codes pop up. I wouldnt bring the car back in until you have done this to be honest because you are likely going to be wasting your time. If the car has bad gas it will likely cause inconsistent temp readings in the cylinder banks based on where the shitty gas fired off in the motor.

We saw this exact thing at a dyno day in the fall. M4 owner got his car on the dyno and it kept throwing the CEL in the upper RPM range and the computer would pull timing out of the car to protect itself. Tuner suspected bad gas so they dumped some race fuel in and as that gas made its way thru the system the problem went away.

Just my thoughts and opinion. Hoping to save you from a day without your whip!

[MLAW702]

Originally Posted by bb1857

My guess is bad gas and not a faulty sensor. I am bit confused as to how you have had "multiple" fill ups within 480 miles of driving though. Even getting shitty mileage I can go 300 miles on a single tank so my guess is that you got a bad batch of gas and its still in the system. If it was bad enough to throw a code it will have to empty from the system completely. If you have been "filling" up with a couple gallons here and there you are just diluting the bad gas, not removing it. I'd let it run down to empty and fill it back up with a quality gas, run that near dry again and see if any codes pop up. I wouldnt bring the car back in until you have done this to be honest because you are likely going to be wasting your time. If the car has bad gas it will likely cause inconsistent temp readings in the cylinder banks based on where the shitty gas fired off in the motor.

We saw this exact thing at a dyno day in the fall. M4 owner got his car on the dyno and it kept throwing the CEL in the upper RPM range and the computer would pull timing out of the car to protect itself. Tuner suspected bad gas so they dumped some race fuel in and as that gas made its way thru the system the problem went away.

Just my thoughts and opinion. Hoping to save you from a day without your whip!

I think your right. Multiple fill ups meaning 5 gallons here 3 gallons and 2 so that was close to a 3/4 tank. However the past 3 days the car has not thrown any codes or cel lights. So i agree it was the gas. Now why did the shop foreman say it needs a new 02 sensor and bank 1 read lower than bank 2 was probably to satisfy a unhappy owner of a new M or like you said bad gas causing inconsistent temp readings in the cylinder banks. I appreciate your feedback i am gonna keep it until it throws a light again. But so far its pulling like a monster at 600 miles and i cant wait to get my first service done so i can really go full throttle and the so called myth of unlocking more power shop foreman said about 25% is unlocked after the first service .. uh huh sure

[STR8-6IX]

try to avoid filling up at different gas stations, the ECU will be all over the place compensating for each type of fuel.

stick to shell v-power, or whatever is ethanol free in your area.

[MLAW702]

Originally Posted by STR8-6IX

try to avoid filling up at different gas stations, the ECU will be all over the place compensating for each type of fuel.

stick to shell v-power, or whatever is ethanol free in your area.

only filling up at shell we have shitty gas in Nevada so 91 is the highest we get

[STR8-6IX]

Originally Posted by MLAW702

only filling up at shell we have shitty gas in Nevada so 91 is the highest we get

you arent alone on that.. we do have 93/94 octane here in canada but the shell 91 is as good or better.. plus it contains no ethanol.

its either shell or walking for me, lol

[sandjam]

I use Shell V nitro only , even has it labeled on gas filler. Don't cheapen out. Get a fuel rewards card and you can save 0.10 or more per gallon too.

[bmrwrld]

What gas station did you use?

[MLAW702]

ok CEL light came on again and it seems to be at the same corner i turn at. Im thinking maybe a sensor is loose like the mechanic at bmw said. Car has 633 miles. Half tank left should i grab some 100 octane and put 3 gallons so we can rule out the fuel? last stop i filled up at was chevron but why did it last a half tank then came on if it was bad gas? wouldnt it come on sooner than that ?

[MLAW702]

Originally Posted by bmrwrld

What gas station did you use?

shell then chevron. i was told stay away from wholesale gas like sams club costco and arco

[Sleeper]

Originally Posted by MLAW702

shell then chevron. i was told stay away from wholesale gas like sams club costco and arco

If your car is throwing a CEL, it'll store a code that the BMW techs can read. I wouldn't run around trying different fuel - something is clearly wrong. Let them scan it and figure it out. You shouldn't be wasting your time troubleshooting a brand new car.

[Alpine300zhp]

Originally Posted by STR8-6IX

try to avoid filling up at different gas stations, the ECU will be all over the place compensating for each type of fuel.

stick to shell v-power, or whatever is ethanol free in your area.

Yep. I run Shell V power only. In a pinch, I'll put in Chevron, but it gets the best power and fuel economy on Shell.

[Alpine300zhp]

Originally Posted by sandjam

I use Shell V nitro only , even has it labeled on gas filler. Don't cheapen out. Get a fuel rewards card and you can save 0.10 or more per gallon too.

Good advice. My fuel rewards card gets healthy use. 2-3 fill ups a week. Nice savings for doing nothing except swiping a card.

[MLAW702]

Car is at BMW getting o2 sensor replaced said they had to take off the intake manifold and waiting on gaskets . Car has just under 700 miles now. Hopefully this fixes my problems I didn't spend all this money for my car to be in the shop
And the fact it has to be worked on for a few days . Meanwhile I'm in a 330i loaner :thumb downs

[MLAW702]

still waiting guys guess they are keeping it another night for running tests

[r20]

Originally Posted by MLAW702

Now why did the shop foreman say it needs a new 02 sensor and bank 1 read lower than bank 2 was probably to satisfy a unhappy owner of a new M..

I also think it's because BMW techs are probably the worst in the industry.

Anytime they get your car, they try to find something wrong with it, so they can hit BMW NA with a repair charge. (Because of free maintenance).

I went Saturday because my steering wheel vibrated on a 328 with 7k miles.

Sales tech came out said they are changing my rear brakes and rotors.

Took it home, hit the brake, still same shake.

Next time I go back theylll replace front and make me pay for an alignment. And that'll solve the problem

[al3xander]

Originally Posted by jxr006

I also think it's because BMW techs are probably the worst in the industry.

Anytime they get your car, they try to find something wrong with it, so they can hit BMW NA with a repair charge. (Because of free maintenance).

I went Saturday because my steering wheel vibrated on a 328 with 7k miles.

Sales tech came out said they are changing my rear brakes and rotors.

Took it home, hit the brake, still same shake.

Next time I go back theylll replace front and make me pay for an alignment. And that'll solve the problem

Why would free maintanence affect it? You know techs get paid to do the free maintanence Right?

[MLAW702]

Car is running flawless and feels a tad slower but that might be me getting used to the power now.

[morf13]

Originally Posted by MLAW702

I was very excited to become an M4 owner after waiting so long to finally be able to afford one.

Last week I pulled the trigger on a 2017 M4 Black Sapphire with Carbonstructure interior. After only 100 miles the drivetrain malfunction light came on and the car went into limp mode. The car reset after shutting off, but the check engine light remains on. Though the drivetrain malfunction light is gone. I took it to the dealer the next morning. They read the codes and blamed it on bad gas.

After much thought and some online research it appeared this could be the issue so I gave them the chance and topped it off with more 91 octane. The light has been on and off all week after several fill ups at different gas stations. I took it in to BMW yesterday and waited for three hours for them to tell me its a bad NOx/O2 sensor by the intercooler and he cant see if its loose cause the car it too hot. Bank one read higher than bank two (whatever that means) so they ordered a new sensor and will need the car a full day to replace. Hopefully this solves my issues. Very frustrating buying a brand new car when I can't drive it and break it in properly.

With having only 700 miles i got a defective FEM and the car stopped recognizing the keys and the engine ignition wouldn't start. After a week in the shop they fixed the problem by replacing the part and now its been about two months and it's all good.