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.

gta3005 said:

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.

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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.

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:

gta3005 said:

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:

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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.

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

Check into your warranty. The battery and gas engine have special warranties on them that extend past the vehicle warranty.

gta3005 said:

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

Check into your warranty. The battery and gas engine have special warranties on them that extend past the vehicle warranty.

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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!

Just to close out (hopefully) my experience with this cel, here was my experience.

BMW ended up having the vehicle for approximately 3 months. A rental was provided for essentially this whole time. This was apparently because NY salt had destroyed a lot of parts, so they were stuck ordering a couple parts and waiting. In the end, they told me it would've been around $12k in parts and labor. Finally got it back a couple weeks ago and the gas motor honestly sounds a lot quieter. They wouldn't tell me what the issue was in the end, and i didn't want to push my luck getting the whole thing covered.

After finally getting it back, a couple days later, i got another cel. Brought it in and said the 12v battery was on its way out, estimated $500 job. They said it was likely from sitting so long, which i would have been more upset about if the battery wasn't the originally at almost 10 years old. I put it off, trying to source the difficult to find Remy battery, until this past Saturday when i found the car in the typical completely dead 12v battery where it wouldn't start. I sourced a similar Duralast TX24HL battery for ATV's that i had seen people talking about on Reddit. Took about 30 minutes to replace and had to purchase bimmerlink, overall very easy!

And now I'm back to a mostly functional vehicle! Next job is both front wheel bearings which don't seem too horrible...