REX maintenance question

Hi all,

Today after unplugging the car after a full charge I got a warning in the dash concerning the REX. However, the message disappeared fairly quickly
so I couldn't read the full message and only a warning sign stayed in the dash. As far I understood it was saying something about a automatic maintenance from the REX. I then switched off the contact to open the garage door and then switched it on again. Now I received the message, "automatic maintenance currently not possible" and suddenly the triangle warning sign in the dash went away. Then I went to car status to look at the error messages and there everything was ok, no faults .

Someone already experienced this or knows what this means ?

It means that the REx tried to start it's automatic (every 90 days or so I think ) short maintenance run (10 minutes), if it hasn't seen any use recently, and wasn't able to either because your battery is charged at over 75% (there needs to be battery room for the REx to generate the electricity to), or you shut off the car before the REx started itself. Just drive the car normally (and let the battery go down below 75%) and the REx will run it's cycle, and the messages and warning icons will go away.

MKH said:

It means that the REx tried to start it's automatic (every 90 days or so I think ) short maintenance run (10 minutes), . . .

Click to expand...

Roughly every 60 days for ~6 minutes.

Bob Wilson

He guys, thanks for the reply and useful information, my wife was scared to drive with the car today so this will reassure her.
I think it is about 35 or 40 days ago that I drove the REX for emptying the fueltank so I could fill it u with new fuel since I didn't
now how old that was.

Last time my REX turned on to run the maintenance cycle the battery was at roughly 85%.......never before done it over 75%, I wonder if there has been a software update?

Mine did it exactly on the 75%, it started right up and the warning in the dash was gone.

It also wont do a mtce run if the fuel is too low, wont let you open the fuel flap unless the fuel is low and battery state is below 75%.

I tend to give the REX a run for 10 mins each 2 months when on a journey, as its annoying when it starts to come on with a short trip only to get shut down and it tries again each short trip until its satisfied, with all the error messages.

The worst feature is when the handbook says the way to cancel the run for a more convenient time is to press the start button.

doing this with the car not driving just shuts everything down. Doing it with the car moving puts it into neutral and when it gets slow enough it will lock the transmission (dont ask me how i know)

i do wonder if this is why early i3 needed new motor mount brackets and bolts

If anyone has a different interpretation to the "how to cancel Rex start for mtce" please say - for now I let the car do its thing

I have same problem, but its persisted for months. I rarely use the rex and cant remember when i've filled tank.

How full does the tank need to be to enable this maintenance? it has been showing 14-mile range on REX forever.

I finally used the REX two days ago and thought that this would go away, but no luck.

The REx needs to run for 10-15 minutes during its maintenance cycle. An indicated 14-miles may not be enough fuel to ensure it can do it from a cold start. IMHO, not running the REx often enough is likely one of the sources of problems. From messages, it appears that a lot of the issues are from moisture getting into places it shouldn't. It takes heat to both drive that off, recoat everything with oil internally, and dry things out. If I had a REx, I"d probably try to run it at least once a month, and if you live where it rains a lot, maybe even more often. You really want to get it up to full temperature for a bit to ensure you've driven all of the moisture out of things. It also takes time to fully heat the exhaust and catalytic converter to drive all of the moisture out of it from the engine running. It needs to be hot enough to stay steam until it exits, and that takes time.

Sorry for the duplicate post from an earlier topic.

With my driving habits, I don't need the REX. So, other than the maintenance cycle, it doesn't run. After two years of this pattern, a check engine light and a smell was diagnosed as bad gas. Now, every six months, I run the REX to drain the gas. ( I coded 'hold charge' for convenience.) I picked six months without any scientific facts. Is six months a good interval?

I'd run it for 10 - 15 minutes every 3 - 4 months. You might also add a gas stabilizer. I add PRI-G to mine, as that is what the military uses in their fuel storage dumps and in emergency generators to keep fuel fresh where it may sit for years before being used.

https://www.amazon.com/Small-Engine-Gasoline-Treatment-Bottle/dp/B005JP0A9C

(The only difference between PRI-G regular and PRI-G Small Engine is the concentration. The Small Engine stuff isn't as concentrated, so easy to measure/use for small fuel tanks.)