gta3005
Posts: 8
Joined: Thu Feb 07, 2019 5:23 am

Re: Replacing REX fuel temp/pressure sensor

Well I've got good news and bad news. Codes are currently clear, so that's good. But unfortunately the guy that did it isn't willing to detail what he did to fix it, so thats not great news.

Here's my guess. Replacing the fan doesn't seem to have immediately fixed the issue, so I wouldn't start with this. This leaves 2 other options we haven't looked into yet. First, I did find a thread on this forum with someone having a similar issue. They determined it to be the fan fuse at position 121 (not the original fuse we checked for the fan relay). The other option is the relay itself. There's a possibility my guy was able to test the relay in the vehicle and force it to function again. The one thing that leads me to believe this was the solution is he did mention the relay was probably bad and should be replaced soon (after inspection passes). He did also mention the relay should be matched to the vehicle through software, so you might create some other issues if you just replace the relay and don't have someone to reprogram the vehicle afterwards.
tangocash
Posts: 32
Joined: Sat Aug 25, 2018 11:51 am
Location: Los Angeles CA.

Re: Replacing REX fuel temp/pressure sensor

gta3005 wrote: Thu Sep 29, 2022 5:10 am Well I've got good news and bad news. Codes are currently clear, so that's good. But unfortunately the guy that did it isn't willing to detail what he did to fix it, so thats not great news.

Here's my guess. Replacing the fan doesn't seem to have immediately fixed the issue, so I wouldn't start with this. This leaves 2 other options we haven't looked into yet. First, I did find a thread on this forum with someone having a similar issue. They determined it to be the fan fuse at position 121 (not the original fuse we checked for the fan relay). The other option is the relay itself. There's a possibility my guy was able to test the relay in the vehicle and force it to function again. The one thing that leads me to believe this was the solution is he did mention the relay was probably bad and should be replaced soon (after inspection passes). He did also mention the relay should be matched to the vehicle through software, so you might create some other issues if you just replace the relay and don't have someone to reprogram the vehicle afterwards.
Thanks for all the detective work! I checked the 121 fuse and (unfortunately) it looks fine. I really wished that were the issue so this could be a cheap and easy fix.

Now I have to figure out who I can send my car to for programming, once I swap out the relay. While I'm typically leery about the expertise of indy German shops when it comes to electric cars, this relay issue sounds pretty basic for any BMW. I wonder if swapping the relay before I go to shop will cause any issues or is it just a recommendation that you get the relay programmed "as soon as possible" to avoid future computer issues? I'd really rather do as much of the work myself to avoid additional labor costs and time spent waiting for parts to be ordered when I really just need the shop for their computer.
2014 BMW i3 REX
gta3005
Posts: 8
Joined: Thu Feb 07, 2019 5:23 am

Re: Replacing REX fuel temp/pressure sensor

Reviving this thread with a quick update. CEL came back on after inspection. Replaced the cooling relay hoping that would clear it. Ran the engine to try and clear it and within a mile of running the engine shut off and said to contact service. I couldn't get it in to my guy because he's out of town for 2 weeks so I took it to BMW. They said they were having difficulty translating the codes so they needed to send them to BMW headquarters. Heard back today that it needs a new gas motor. Service rep was going thru the numbers (~5g labor, waiting on motor cost) and i reminded him the gas motor is still under warranty. So that's where I'm at :shock:
tangocash
Posts: 32
Joined: Sat Aug 25, 2018 11:51 am
Location: Los Angeles CA.

Re: Replacing REX fuel temp/pressure sensor

gta3005 wrote: Mon Nov 28, 2022 7:29 pm They said they were having difficulty translating the codes so they needed to send them to BMW headquarters. Heard back today that it needs a new gas motor. Service rep was going thru the numbers (~5g labor, waiting on motor cost) and i reminded him the gas motor is still under warranty. So that's where I'm at :shock:
YIKES! Thanks for the update and sorry for the hassle you're dealing with. I'm so curious what BMW would attribute to the entire motor failing and needing to be replaced as a unit, rather than just replace a few parts, but I doubt they'll want to share details, and/or admit issues with their motor.

My i3 is a 2014 so NO warranty for me. I was holding off on getting the code looked at until it was more convenient, but now I'm not so sure I want to address it all. At least the motor is working well at the moment, and I'm not getting any urgent service messages. I want to squeeze another 2 years out of this car, before I move on to a new EV.
2014 BMW i3 REX
gta3005
Posts: 8
Joined: Thu Feb 07, 2019 5:23 am

Re: Replacing REX fuel temp/pressure sensor

I'm in a 2014 also. The gas engine has a 15 year 150k miles warranty on it. Got approved by BMW NA today for the warranty work :D

Check into your warranty. The battery and gas engine have special warranties on them that extend past the vehicle warranty.
tangocash
Posts: 32
Joined: Sat Aug 25, 2018 11:51 am
Location: Los Angeles CA.

Re: Replacing REX fuel temp/pressure sensor

gta3005 wrote: Tue Nov 29, 2022 6:07 pm I'm in a 2014 also. The gas engine has a 15 year 150k miles warranty on it. Got approved by BMW NA today for the warranty work :D

Check into your warranty. The battery and gas engine have special warranties on them that extend past the vehicle warranty.
AH! I had no idea there were separate warranties since I bought this from a used dealer, but boy do I feel better now. I've had nothing but questionable interactions with my local BMW dealer so I avoid going to them at all costs and do most maintenance myself, but I'm on the hunt for a reputable shop in case of major issues like this. Thanks for the insight!
2014 BMW i3 REX

Return to “Problems / Troubleshooting”