A curious issue has come up with my 2016 F55 Cooper. Every time I get into the car, the screen tells me to reset time and date (the computer also forgets trip mileage, MPG, etc.) and the check engine light is on.

I dutifully reset the clock and date each time, but the system forgets again when I get in the car the next time. Resetting the check engine light doesn’t work...it comes on again the next time I start the car.

My reader tells me it’s a P15E8 error. That error, among other things, includes “Collateral fault from incorrect time signal from the instrument cluster” as a cause.

That fuse diagram does not really tell me much, so I’d like to check the proper fuses, but I don’t really think this is a fuse issue.

(Full disclosure: I just installed a Homelink mirror last week, right before the clock problem came up. But the mirror gets its power from a fuse tap I plugged into an unused socket, and it gets ground from a screw under the dashboard. No factory wires were touched. I don’t see how the Homelink would impact the clock/computer.)

Any ideas about how to fix this problem?

 

Any chance the mirror install is causing a battery drain?

 

I don’t think so. If I reset the clock (oddly, sometimes the date stays set) and then turn off the car, in as little as a couple of minutes, the thing needs to be reset again when I check. All the other electronics work fine, the car starts easily, the battery is 7 months old, and the car lives in a 40 degree garage (as opposed to out in the 18 degree winter battery-killing cold night).

On the off chance the service indicator was the issue, I reset all my service intervals. Didn’t help.

 

To Minnie's point, is the mirror tapped in to an Acc fuse or a Constant?

 

It had been constant power, I'll move it to an acc fuse but first I'm testing to see if the clock needs a reset while the mirror is not connected to power at all. This morning I left the car on a battery charger and the time showed --:-- when I checked. But the mirror was powered at the time.

So now the car is off, the code is cleared, the time is set, the mirror power lead is disconnected, and the battery is on a charger. I'll give it half an hour and see what happens.

I did locate a post where someone's R56 had an identical issue and the cause was a weak battery so I am working that angle now (since it's all I've got to go on at this point.)

Stay tuned...

 

Ah okay cool. Good luck!

 

With the mirror disconnected, the battery on a charger, and the error code reset, the car still needed the clock reset. I’m at a loss here. Anyone have any ideas?

 

At the end of the day the problem was the battery. When I replaced the original battery last July, I didn’t have the battery registered with the car because our closest dealer is two hours away.

By December it caught up with us and caused a low voltage fault. New battery, registered by the dealer, and everything is working properly.

The dealer experience was a reminder of why I don’t like using the dealer. But they did fix a problem I couldn’t resolve on my own.