BMW i3 REx without REx

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mrken

Member
Joined
Feb 11, 2021
Messages
11
Looking to get a higher-mileage 2017 BMW i3 REx as my only vehicle. 10-mile daily commute round-trip with occasional trips that may exercise the REx.

If the REx fails at some point in the future, does the i3 just function as an overweight BEV? Or would a broken REx affect the purely EV part of the i3?
 
I guess would depend on the type of failure. I seem to remember an i3 owner in the Pacific North West with a failed REx engine which the dealer quote to repair was excessive. Owner had no problem driving the car as a Bev, other than the constant engine check light, and a warning at startup that only electric drive was possible.

That said, the REx engine is pretty solid. It's the same engine BMW uses in their BMW 650 scooter. They are manufactured by Kymco in Taiwan. Kymco has been around since the early '60s and were the main manufacturer for Honda's small engine parts at one time. They are now the 5th largest scooter/small engine manufacturer in the world with $one billion in annual sales, and a good reputation for building robust, quality engines for scooters, motorcycles, ATVs, generators, etc.
 
Thanks MKH for your detailed response! I hope to drive this i3 for another decade and can live with the CEL if the REx dies.

I am looking at this 2017 BMW i3 REx, but the Carfax service history shows the A/C refrigerant needed recharging only 3 months and 4990 miles after purchase:
https://www.carfax.com/VehicleHistory/p/Report.cfx?vin=WBY1Z8C3XHV893127

I have read your very helpful posts on the catastrphic failure of some air conditioning systems and am wondering if this is something to be concerned about.
 
mrken said:
I am looking at this 2017 BMW i3 REx, but the Carfax service history shows the A/C refrigerant needed recharging only 3 months and 4990 miles after purchase:
https://www.carfax.com/VehicleHistory/p/Report.cfx?vin=WBY1Z8C3XHV893127

I have read your very helpful posts on the catastrphic failure of some air conditioning systems and am wondering if this is something to be concerned about.

I would be asking about that, yet since it was within a few months of new - my bust guess would be that it came low from the factory.
Yet that service record is weird in the beginning the owner came in every 5k miles? To get the tires checked?

My 2017 i3 had exactly one Service appointment until 40.000 miles and this car had 9 ?
Maybe that's one of the dealers which offers free carwash and coffee when you are in the area :p no idea
 
My info is that the catastrophic AC failures were due to a small batch of defective AC units installed in some 2014 and 2015 i3s. Have not heard of a failure in a year or so, so assuming that all those bad units have failed, and/or been replaced by now. Since the AC service was very early on, with no recurring issues, not something I'd be worried about. From the Carfax I don't see anything too unusual. Looking at mileage, the service intervals look about normal, other than they are also using the dealer for tire service/replacement, so seems like a lot of service trips until you separate out the ones that are just tire service. Looks like they had one tire with a slow leak that was checked, then eventually replaced - probable nail damage, then took it in to have two worn tires replaced and decided to do all four, at pretty typical end of life wear mileage. Also listed are the typical pre-trade in dealer valuation service checks, followed by the dealer prep-for-resale service.
 
Bought it! The previous dealership had spent more than $3000 in the pre-sale service, including changing 3 of 4 tires. Seems like it has sat for at least two months since the REx wanted to run its maintenance cycle as soon as I started the test drive. Air conditioning at the lowest temperature seems to blow reasonably cold air without issues.

However, found a few (hopefully minor) issues. The last 2" of the driver door seal was torn. The driver seatback fabric ripped open. Would these be covered under the 4-year warranty?

At the dealership, the driver heated seat would not turn on (no lights, no click), but the passenger heated seat turned on fine. Figured it may have been a blown fuse and did not investigate further. Tried again the next day after a long drive home, and the driver heated seat turned on and works perfectly! What would cause it to start working again?
 
Congratulations!

You can try getting the seat cover and door seal replaced under warranty - though the dealer may claim that it is 'wear & tear' so not covered. If they won't cover it, the seal should be a fairly easy DIY, getting the part from one of the online BMW parts stores. The replacement seat covers are expensive from BMW - $600+. You can usually find seat cushions from salvage cars on ebay for under $200, all the way up to the complete full leather i3 seat sets for $900 ish. There is also an i3 owner who posts on the i3 Facebook group who does custom i3 seat covers.

The seater heater glitch may have been due to a low 12v battery because the car sat for so long. The 12v accessory battery powers on all the car's ECUs at start-up, and then the DC/DC converter takes over supplying power from the HV battery pack to run the systems. If the 12v was really low, may not have had the juice to turn on all the systems. Alternately, some have reported intermittent component fails in the climate control panel. If it happens again, take it in for a fix under warranty.
 
mrken said:
At the dealership, the driver heated seat would not turn on (no lights, no click), but the passenger heated seat turned on fine. Figured it may have been a blown fuse and did not investigate further. Tried again the next day after a long drive home, and the driver heated seat turned on and works perfectly! What would cause it to start working again?

Congrats!

The seat heater is a surprising complex system. It has two sensors to determine the temperature (which you can adjust) then it detects when someone is sitting on the seat, further if you put in ECOpro or + it heats less (so low that you wont even feel it)

Really hard to guess what was wrong with it.
 
Thanks MKH and eXodus for your continued help!

Went to the dealership today but they cannot diagnose the car until tomorrow. :( Hopefully they will cover the repairs!

The service advisor looked up the service at 3 months and 4990 miles and saw it was for a failed A/C expansion valve, which explains the need to recharge the A/C refrigerant. This does not seem like a common problem on the i3?

The driver heated seat turned on today, but turned itself off during the drive to the dealership and would not turn back on. The 12-V accessory power measures around 14.3 V. Could my weight on the seat be shorting the heating elements? I will have to test the passenger heated seat while sitting on it when it comes back from the dealership.

It is actually the backrest fabric, not the seat covers, that was detached from the from the plastic frame, like this:
https://www.jesseweb.com/tech/repairing-the-bmw-i3-backrest-fabric/
Sorry for being unclear earlier. If the repair is not covered by the warranty, I can probably reglue it myself with some effort.
 
If the dash led lights for the seat warmer don't flicker on and off or only light up a few of them, likely not the dash unit at fault. Sounds like a short in the actual heating mat - has happened when someone kneels on the seat a lot, which can stretch and eventually break one of the heating element wires. All the ones I've heard of this happening to, BMW replaced under warranty.

Measuring the 12v from one of the power sockets won't give you a clear picture of the actual 12v battery voltage. As soon as the car 'wakes up' and the 12v initializes the ECMs, power to the sockets comes from the DC/DC converter and the HV battery pack, not the 12v. The 12v battery in the i3 is an 'accessory' battery, about half the size of a normal car battery - basically powers the door locks, alarm, diagnostic monitoring, and boots up the car's computer systems.
 
mrken said:
The driver heated seat turned on today, but turned itself off during the drive to the dealership and would not turn back on.

I recently had the same problem, which was due to a broken seat temperature sensor. The seat cushion needs to be replaced as the heating element and sensor are integrated - this should be fixed under the warranty.
 
Finally got the car back from the dealership today after 3 days in the shop! Just past the 5-day return period.

They were able to replace the heated seat mat, seatback fabric, and door trim under warranty. The heated seat works perfectly now. :D

They would not repair a small cut in the trunk seal though, attributing it to "external factors". It probably got cut when removing or reinstalling the cargo cover.

Spent a bunch of time trying to program the Homelink unsuccessfully. The yellow LED flashes as soon as I press any button so have not gotten past the erase all programming stage. Will try again tomorrow.
 
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