I have to keep my car on a trickle charge in the winter as it sits alot or it gets to throwing codes. I have a newer battery.

 

Resurrecting this thread - its winter here, so I'm having the P15e8 code again on my '09 R55....the date and time drop to zero's every time I turn the car off now that it's cold....and this code occasionally shows up. I have a battery that is about 18 months old....registered when it was installed.

I think the cause of the p15e8 code is that the time goes to zero and the ECU thinks that the temp dropped implausibly quickly. I don't know what the cause of the constant time and date going to zero...just started again with the cold weather. no other issues...starts fine, heater blows fine, etc.

 

* MINI DTC P15E8 (0x3392) - Engine shutdown time, plausibility: Time too short relative to temperature drop in engine coolant
The diagnostic function monitors the engine's calculated downtime by comparing it with the drop in coolant temperature while the engine is stationary.
The time required for engine cooling is implausibly short relative to the calculated time.

Potential problem source(s):
- Instrument cluster disconnected from Terminal 30 during stationary phase (battery change)
- Collateral fault stemming from a defective engine temperature sensor
- Collateral fault from incorrect time signal from the instrument cluster

I would check / replace the temperature sensor and clear faults. See what comes back.

- Erik

 

My wife started the car the other day and we had a red car on the lift symbol on the cluster, and the blinkers didn't work. It was on her way to work so I couldn't look at it. I did some quick searches and what I found everything pointed to the footwell module. She later sent me a message saying windows and dome light didn't work, which all pointed to that module. On her way home the red warning was gone and there was just the little triangle warning light. Her blinkers and everything worked, but then the dash lights randomly flickered on and off. I went out and took it for a drive and couldn't reproduce anything, everything seemed fine. I had checked the connections and everything seemed ok. I scanned the codes and got the P15E8. I cleared it and the symbol remained. I scanned again and no code.... Was weird. I drove around for awhile and reset the clock for my wife since I was just out for a drive. The light went out as soon as the clock was set. Crazy. Not exactly sure what my problem is, but I'm wondering if maybe it is my battery in the end. A couple months ago it was testing good but always said it needed a charge, would only charge to 51% or something like that. Never tested as a bad battery though. Maybe it is time to just replace it.

 

Could be as when the battery is bad in a MINI all sorts of weird electrical Gremlins will occur. What did the battery test at? If it's not holding its charge and it hasn't been replaced in a while, replace it. Batteries that also sit for long periods of times or only do short drives are not given enough time to recharge during the drive cycle. If it does sit and you only take short drives, you'll want to invest in a battery tender HERE to help prolong the life of your battery. The battery is the cheapest place to start, especially if it's the original or hasn't been replaced in a while.

 

When I tested it it just said it was good but needed to be charged. Alternator tested good too. We live in the middle of nowhere so anywhere we go is a bit of a drive. We have had the car for 3 years and haven't changed the battery at all, not sure how old it was before that. So it very well may need a battery. I wonder why the battery always tests good and that it just needs to be charged. I have to go on a decent drive tomorrow, so hopefully it behaves.

 

So when you test it with a voltmeter is it giving you a reading of 12 volts or under? If so, battery needs to be replaced. I have even seen a battery at 12.2 volts that was bad. A normal reading would be about 12.6 volts. The battery is perhaps the most important electrical component on the car, and due to its design and nature, is perhaps one of the most troublesome.

 

I don't remember. It was over 12, but may have been 12.2 or 12.4. If I get time tomorrow I will test it again.

 

Tested as "good needs charge" after driving it for 2 hours. 12.25 volts

 

I've seen bad batteries at 12.2 Volts before. 12.6 volts is ultimately what you want. I am still thinking it's a battery issue at this point, but wont know until you test with a new one.

 

Have you load tested the battery? Your symptoms are the usual typical battery ready to take a dump. Your battery shouldn't need a charge after driving 2 hours, battery starts the car and once you start the engine charging begins via the alternator at 14.2 volts. A battery in excellent condition should reach full after only 15-30 minutes of driving. I would also have a look at your alternator as this can kill a battery by undercharging it.

Up until 2014 I was only the original battery that came with my Mini back in 2007 and it only died because the body shop left a light on for a week, other than that it was still strong and showed no signs of quitting. I drive on the freeway 26 miles (13 miles one way) round trip M-F.