[Aceattack52]

Hey guys,

(2013 328i, N20 engine)

I have owned several BMWs in the past but this is my first experience with one that is this new. The car came with some mechanical issues that I have sorted out and tested and all is well with that.

Now that everything is fixed, I am having trouble passing emissions. When I drive the car I don't get a check engine light or any warnings. Some of the emissions monitors will set as I'm driving. If I let the car sit for more than about 20 minutes, the computer resets and erases the monitors that just set. The trip mileage and clock are unaffected.

I read on the forums here that it could be an issue with an aging battery- I have replaced the battery and notified the car of the replacement battery in ISTA.

To pass emissions where I live, you have to have all but one emission monitors set. If the computer keeps resetting itself, I don't think I will be able to pass.

If this is an ECU problem that could be covered under the federal 8year/80,000 mile emissions warranty (catalyst, PCM and ECU are the only things covered for that length of time), my car is sitting in the driveway with 79,988 miles and it is a 2013 MY.

Thank you for the help

[chowser51]

It may be a 2013 car but when was it manufactured or in service date?

My model year 2019 went into service 11/2018.

[Aceattack52]

The sticker on the door jamb says 12/12

[visionaut]

Maybe you didn’t complete the full ‘conditioning road test’ aka the emissions readiness driving cycle?

I assume you have a code reader, so you can clear codes, but more importantly see which readiness items are completed and not.

The attached info is hopefully useful…

[Aceattack52]

That's correct- I have not completed the full drive cycle. To complete the drive cycle it will require more than one warm-up cycle. If I leave the car for more than 20 minutes, it erases the computer's memory. So I can drive it to warm up once and get some of the monitors ready, but there is no way I can get any monitors that rely on more than one warm-up cycle since the computer's memory erases before the car can cool down enough.

I did not mention in my original post, but further evidence that it is not the battery is that I have kept the car on a charger and it will still erase the memory after about 20 minutes.

[visionaut]

I’m not aware of the readiness states being storable over any extended period… the RCs are not stored like fault codes.

[thejeremyman9]

Originally Posted by visionaut

I’m not aware of the readiness states being storable over any extended period… the RCs are not stored like fault codes.

They should be stored over a vehicle restart though. I'm just not sure OP is reading them correctly though or maybe accidently clearing when reading?

[Aceattack52]

Originally Posted by thejeremyman9

They should be stored over a vehicle restart though. I'm just not sure OP is reading them correctly though or maybe accidently clearing when reading?

I believe I am reading them right. I have an Ancel code reader with the I/M readiness function that I've used on many cars including other F30s. Additionally, there is more evidence that the computer is resetting itself after about 20 minutes in that the air conditioning turns on with the car after the computer resets. Any fault codes I create by unplugging a sensor and turning the car to run are present after turning the car off but are also cleared after 20 minutes of the car sitting.

[Aceattack52]

~~~SOLVED~~~

After some searching online and some diag on the car, I found that there was a ~1 amp parasitic draw from the battery when everything went to sleep. The device drawing the power was the instrument cluster on fuse #50. This seems to be a common problem and one that can only be solved by replacing the cluster.

So I went to ebay and bought a 6WA cluster to replace my basic cluster in the car. It looks great and works well after I had it coded in by Code My Bimmer. After talking to Steve after the coding, I explained the problems I was having with the car not retaining the emissions information and he said that it makes sense that replacing the cluster will fix that problem because the emissions information is stored in the cluster. That seems strange but it did fix my problem and I will be able to get my emissions done soon!

[thejeremyman9]

Originally Posted by Aceattack52

~~~SOLVED~~~

After some searching online and some diag on the car, I found that there was a ~1 amp parasitic draw from the battery when everything went to sleep. The device drawing the power was the instrument cluster on fuse #50. This seems to be a common problem and one that can only be solved by replacing the cluster.

So I went to ebay and bought a 6WA cluster to replace my basic cluster in the car. It looks great and works well after I had it coded in by Code My Bimmer. After talking to Steve after the coding, I explained the problems I was having with the car not retaining the emissions information and he said that it makes sense that replacing the cluster will fix that problem because the emissions information is stored in the cluster. That seems strange but it did fix my problem and I will be able to get my emissions done soon!

Thanks for updating the thread with the solution, very interesting indeed as you would not expect those to be related.

[visionaut]

Originally Posted by Aceattack52

~~~SOLVED~~~

Wow. I wouldn't have thought about the cluster itself...

So the car 'protected itself' from getting a dead battery from the excessive drain by shutting stuff down, like the power to keep the cluster memory 'live'. That's why the bad-battery part seemed to fit.

Surprised there wasn't ever a code stored - when my car sat at the frigid airport once for 2 weeks while I was away, the car went into self-preservation mode for the battery - but there was a iDrive message and code stored recording that it did that when I returned. Maybe it shut down that temporary code retention too.

Thx, Ace, for updating with the solution for future reference!