[Hovis]

Well my i3S Rex is 29 months old, has done 23000 mile and has been fault free until now. The engine warning light came on yesterday and hasn’t gone off. I went out in it today and it’s still on. Over recent months its not been used that much, but Ive had to do some long trips recently and the Rex has been used regularly. I’ve just checked again and its still illuminated, but oddly the outside temperature reading is way off. It’s showing +50 Celsius, when the actual outside temp is more like + 6 C. Don’t know if that linked to the engine warning light or not.

Also the fuel cap door isn’t locking, i.e I can push and open the door without pressing the pressure relief button!

Can’t remember, but shouldn’t the fuel cap door lock itself when you lock the doors, or after closing it once you’ve refuelled? I’m sure when you lock the car, all doors and the charge and refuelling doors should be locked?

The outside temp reading is a puzzle, but maybe the engine warning light is linked to the fuel cap door.

Contacted the dealer and they have said not to use it and they will have to have it in for a check on diagnostics, but they can’t get me in for over a week! Any suggestions.

 

[spartacus]

I wouldn't worry about it, you've a few months left on the warranty, and it's a little impractical to say not to use it, if it's your only transport. If the REx had a major fault such as fuel pump or fuel pressure switch then the REx just would't fire up at all and you'd be on electric only.

They'll hook it up to their diagnostic software and read the codes, then start pulling out parts until they fix it.

The fact the outside air temperature is out by 44 degrees would suggest the ambient air temperature is goosed, but of course that data will be used for the efficiency of the engine. Where possible - try to run on electric only until they check it out. Suspect its a temperature sensor.

 

[Hovis]

I got the age of the car wrong, it’s actually only 24 months old, this lockdown is frying my brains! 🤪 So its still got a year on the warranty. 👍 I’ll have to look at extending the warranty next February.

Ive been out to the car again, to see if the locking mechanism is working. I can hear a noise from the filler flap, as though its trying, but it doesn't lock. So I squirted some WD-40 into the locking pin area, but this hasn’t made any difference.

 

[spartacus]

I got the age of the car wrong, it’s actually only 24 months old, this lockdown is frying my brains!

I know what you mean. Forgot to say the fuel cap will likely be a solenoid issue. Seem pretty fragile. The solenoid unit uses nylon gears to lock and retract which have probably stripped, especially if you can hear it. I repaired the HV locking solenoid on my wife's car a couple of weeks ago after it iced up. We did have temperatures of -23 Celsius and 2' of snow!

I looked on Hubauer Shop so the outside air temperature is located on driver's side front, under the car. (This is on 2015 REx). If you were desperate you could use contact cleaner, plug and unplug. Hey you're in warranty - chill!

 

[M C Williams]

I doubt if this is anything to do with your problem seeing that you do quite a bit of mileage.

My REX is four years old, and I have known for some time that the 12v battery was on its way out because of frequent messages on the screen.

The final straw was when I had several faults appear on the screen, among them were (!) Above the REX, remote control battery depleted (not true), mileage for the REX and main battery were nowhere near accurate.

The car was due for the MOT, so I had the 12v battery replaced at the same time, it is now great to get in the car with no errors appearing on the screen.

I would think it is unlikely your problem is the 12v battery.

 

[Hovis]

Update, called out BMW Assist today, as dealer said to me not to drive it, and the kind BMW engineer turned up to help me out. I told him about the engine management light, REX filler flap not locking (which I tried to fixed last night, with some WD-40, still faulty last night, but woke this morning to find its now working), and the outside temperature reading showing +50 C. He plugged his diagnostic computer into the OBD2 and after various checks, it pointed the problem to the ambient air temperature sensor, mounted to the underside of the front bumper, accessed from the front right wheel arch. He tried disconnecting it and then reconnecting and then trying to reset the sensor, but appears it toast. So he’s ordered a new sensor and is returning tomorrow, to fit it and clear the fault codes.

Fingers crossed this will fix it, and excellent service from the BMW technician. Will update Saturday on the outcome. 🤞🏻

Update Saturday 27th: All fixed, new external ambient temperature sensor fitted by BMW tech Jonathan, at my home. All fault codes removed and back to normal. Very pleased with the service and Jonathan’s Customer service.

 

[MarkyM]

That is good to hear. I have had these BMW assist guys out to the house twice in 4 years since I have had the i3-mainly for fault code diagnosis. Very helpful and knowledgable and under warranty- FREE to use! So so much better than taking the car to a dealership which they ( BMW HQ) tried and tried to get me to do. Your car will just sit there at the dealership for hours or days before they find the time to look at it. This engineer to your door (at home or work) is so much better. And your time is not wasted. They also told me they are often looking for work and happy to come to help but BMW and the other companies they work for (typically Mercedes and Porsche) don't like using them as it costs them more money!