Replacing REX fuel temp/pressure sensor

[tangocash]

My check engine light came on recently and the OBD scanner w/ Torque app gave me 3 error codes which, when "translated" online, came to:

P14FA - exhaust gas temp sensor faulty
P0185 - fuel temp sensor B circuit malfunction
P018B - fuel pressure sensor B circuit range/performance

I did attempt to clear these code, just to make sure they weren't phantom errors, but they immediately came back.

Unless someone else can tell me differently, I'm focused on fixing the last 2 codes by replacing the sensor part#16147426661 (https://www.genuinebmwminiparts.com/oem ... jsEALw_wcB) that seems to apply to both temp and pressure. I'm hoping that the faulty sensor at the fuel is having a trickle down affect on the exhaust and fixing the last 2 codes will "fix" the first code by default. Or maybe I'm being naive...

I'm wondering if anyone else has received similar error codes and/or replaced the sensor to fix the issue? Figured I'd ask for experiences before I spend $150+ to replace the part myself? I absolutely hate my local BMW dealer and that gives me even more motivation to do nearly every repair/maintenance myself. I just wish I could easily get a confirmation to make sure this is the part I need to fix the issue.

[agzand]

Did you try replacing the fuel pump relay? It is a common fail point for i3.

https://www.amazon.com/gp/product/B00AF ... UTF8&psc=1

https://www.ecstuning.com/b-genuine-bmw ... gJZmvD_BwE

You can switch it with similar relay for other function to see if that is the culprit.

There are videos on youtube on how to do this.

[agzand]

viewtopic.php?t=4527&start=10

[tangocash]

Did you try replacing the fuel pump relay? It is a common fail point for i3.

https://www.amazon.com/gp/product/B00AF ... UTF8&psc=1

https://www.ecstuning.com/b-genuine-bmw ... gJZmvD_BwE

You can switch it with similar relay for other function to see if that is the culprit.

There are videos on youtube on how to do this.

I haven't tried doing anything yet, but this sounds like a much better (and perhaps cheaper) place to start. Thanks!

And I assume I can ignore that fact that both parts you linked to do not confirm fitment on a 2014 i3?

[agzand]

The part number is: 61366915327

I think it is mentioned in this video:
https://www.youtube.com/watch?v=KkF5VvmlZCM

I just think it is unlikely to have several sensors failing at the same time, so it could be the realy.

[tangocash]

The part number is: 61366915327

I think it is mentioned in this video:
https://www.youtube.com/watch?v=KkF5VvmlZCM

I just think it is unlikely to have several sensors failing at the same time, so it could be the realy.

Perfect, that's the exact part number I ordered. Just waiting for it to arrive now.

And thanks for the video!

[tangocash]

Well I replaced the right-hand side relay behind the glovebox, following the video tutorial. I cleared the codes but the check engine light never disappeared. I've been driving the past few days, hoping the occasional use of the REX would clear it, but nothing has changed.

I've now gone back into the computer and found that these codes are now absent so I guess the relay helped after all:
P0185 - fuel temp sensor B circuit malfunction
P018B - fuel pressure sensor B circuit range/performance

But the following codes are still present or new additions:
P14FA - exhaust gas temp sensor faulty (remaining from before)
P0480 - cooling fan 1 control circuit has a malfunction (new code)

Wasn't the left-hand side relay in the glovebox controlling ventilation/air, or am I remembering that wrong?

My A/C has also been struggling to stay cool (colder at highway speeds and not so cold any other time) and that's a separate post, but could these issues be related?

[agzand]

I think the other relay is for the fan, there is also a fuse in the fuse box for the fan.

If the fan works poorly it could be the relay, however I haven't heard many issues with that relay. The fuel pump has more issues because in many cases it is run sporadically.

Also make sure your 12v battery is in good shape and the gas cap works properly.

[tangocash]

I think the other relay is for the fan, there is also a fuse in the fuse box for the fan.

If the fan works poorly it could be the relay, however I haven't heard many issues with that relay. The fuel pump has more issues because in many cases it is run sporadically.

Also make sure your 12v battery is in good shape and the gas cap works properly.

I'll have to track down that fan fuse, just in case.

Yourmechanic.com talks about how to diagnose the cooling fan code and mentions these items to consider so I guess I'll look at doing that when the heat subsides a bit. If I'm really lucky, I'll find some obvious, visual evidence of failure.

-Faulty cooling fan 1
-Poor electrical connection in the fan circuit
-Failed fan control relay has failed
-Failed coolant temperature sensor
-Faulty AC pressure switch
-VSS not operating properly

The 12V was replaced 2 years ago so it feels a bit early to start failing, but you never know...

Thanks!

[gta3005]

Any updates on these issues? I've got the same two codes, p0480 and p14fa ( thanks for providing what this one is!). I replaced the front fan behind the radiator this weekend because that's what BMW recommended but I still have a historic p0480 fault. Going to try running the rex to get it to go away.