[jmciver]

I am not the first to do this, but figured I would share my experience for the benefit of others. Based on my research, my retrofit experience seemed a bit better than some…

As many of you know, those of us who live in North America do not have the M Sport seats as an option for the i4. So I decided to go the retrofit route for my M50. Not that hard as long as you have the correct tools, and of course can source a good set of used seats (since buying new would be ridiculously expensive). I ended up going with G80 M3 seats over X3M/X4M or i4 M Sport seats from Europe. The M3 seats were easier to find on the used market and I found a killer deal on a really nice set that was local to me. Also, I prefer the styling and look of the M3 seats since I don’t plan to re upholster them (but will eventually get the rear seats done to match the fronts).

As far as tools, the most important ones are the diagnostic and coding tools to ensure the car is happy with the seats once installed. I used ISTA for diagnostics and to clear fault codes, and BimmerUtility for the necessary coding. I disconnected the batteries (high voltage batt first, then the 12 volt battery; reconnect in reverse order when done; all per BMW procedures) for basic safety reasons and to prevent getting any airbag faults. While disconnecting the batteries for work like this is always a good practice, I found out later it did not prevent any airbag faults from occurring.

Removing/installing the seats was straight forward. A ratchet and T50 torx bit makes quick work of that. You need to fully raise the seat to get to the seatbelt bolt, and move the seat forward/back to get to the floor mounting bolts. Just make sure you protect your center console and door sill with towels to prevent any scratches when removing/installing the seats. Tightening torque for all of these bolts is 42 nm.

With the M3 seats in the car, plugged in, and power restored, I wanted to see what worked and what didn’t. To my surprise, all seat functions worked. Some others who have done this retrofit with X3M seats have reported that some seat functions, like the headrests, did not function and required additional coding to turn on. I did not have this issue (more on coding below). After hooking up to ISTA I had a bunch of errors, the most important ones being a passenger seat occupancy error and a driver and passenger seat encoding error (which caused the airbag light on the dash).

Using ISTA, I needed to re-calibrate the passenger seat occupancy sensor to the car. This was easy as ISTA will call out a test plan for you to execute that involves sitting in the passenger seat, then getting out, to calibrate it to the car - done. To fix the driver and passenger seat encoding error (and thus the airbag light), I used BimmerUtility (on my iPhone) to VO code the two seat modules to the car. First I read and backed up to my iPhone the original FA in the car. Next, I added option code 711 (M Sport Seats) and removed option code 4FH (Seat Ventillation) to the FA to match the options of the M3 seats I was installing (no ventillation) since my i4 came from the factory with ventillated seats. Then, I saved this updated FA to the car. Next, VO code the driver and passenger seat modules (SM2). Finally, restore and save the original FA back to the car.

After using BimmerUtility as described above, I ran ISTA one more time to clear any residual errors and check for any new faults. The airbag faults (and seat encoding errors) were gone when I turned on the car. The car was now happy. Unfortunately, I could not code the Headunit as the headunit in iD 8.5 cars has yet to be cracked for coding purposes. So I still have the touchscreen control for seat ventillation (which does nothing, obviously), but this does not bother me as it is not visible all of the time.

For the final touch, I wanted to also have illuminated headrest badges. I replaced the M3 badges with the M badges that come on the X3M seats, which I purchased separately. The i4 is not wired like the M cars for the seat badges to be illuminated. I did not feel like running a wire from each seat to the Body Domain Controller (BDC), so I used a wire harness kit that taps power from the ambient lighting at the bottom of the seat. You can see more of that kit in this thread here:

Headrest Badge Wire Harness

So not a difficult install with the correct tools (which are not hard to get and not expensive). In fact, I am kicking myself for not doing it sooner as I did everything in a few hours, including figuring out/executing the coding parts, as the M3 seats have been sitting in my basement for the last several months waiting to be installed. Now I just need to get the rear seats re upholstered to match the M3 seats to help keep my OCD in check 😎..

Thanks for looking…!

[jpuffmasterpuffpuffpuff69]

Very nice!

[therealm3]

Looks great!! Nice write up too.

[jpuffmasterpuffpuffpuff69]

I do want the carbon seats, but not for 10k used + installation. As is, the seats are the biggest performance limiter.

[techwhiz1]

I'd like the seats but I have full individual leather and the chances of finding a set of tartufo seats is pretty slim.

Edit - Just found a set on eBay for $3300..... Hmmmmm

[jpuffmasterpuffpuffpuff69]

Originally Posted by techwhiz1

I'd like the seats but I have full individual leather and the chances of finding a set of tartufo seats is pretty slim.

Edit - Just found a set on eBay for $3300..... Hmmmmm

That seems reasonable.

[techwhiz1]

I just picked up the seats from an X4 M on eBay. Actually the whole interior in tartufo for $2500 + tax and $450 shipping

So I have plenty of spare leather for repairs and such later. It also means my factory seats stay perfect.

I'll have to find the best way to bag and store them.

[techwhiz1]

New drivers seat is perfect.

Passenger seat... Dead

Error codes - passenger restraint and seat monitoring fault.

I need help.

[Technic]

Originally Posted by techwhiz1

New drivers seat is perfect.

Passenger seat... Dead

Error codes - passenger restraint and seat monitoring fault.

I need help.

If no ventilation in OEM seats then wiring is required in passenger seat controller for coding : https://bmwi.bimmerpost.com/forums/s...6&postcount=57

Need ISTA to restart passenger seat monitoring and clear airbag error in M Seats.

[techwhiz1]

Originally Posted by Technic

If no ventilation in OEM seats then wiring is required in passenger seat controller for coding : https://bmwi.bimmerpost.com/forums/showpost.php?p=31212656&postcount=57

Need ISTA to restart passenger seat monitoring and clear airbag error in M Seats.

Thank you but that post doesn't apply. That's for enabling the badges and getting rid of footwell lights

My issue is more fundamental. For some reason the drivers seat is working fine but the passenger seat module fails to be recognized and the seat appears.not to have power.

I have checked all the power connections and I don't see any issues. Where I got the seats.from claim no issues or they wouldn't have been able to unbolt the seats, which is mostly true

I can't see passenger seat module it in the ISTA tree of modules.
When I put my original passenger seat back in, it works, but the car is not seeing the seat module. But I'm not getting errors where it can't find the heater or SRS.

My original passenger seat didn't have lumbar, adjustable bolsters or memory; just heat. Drivers seat had all features.

[Technic]

Originally Posted by techwhiz1

Thank you but that post doesn't apply. That's for enabling the badges and getting rid of footwell lights

My issue is more fundamental. For some reason the drivers seat is working fine but the passenger seat module fails to be recognized and the seat appears.not to have power.

I have checked all the power connections and I don't see any issues. Where I got the seats.from claim no issues or they wouldn't have been able to unbolt the seats, which is mostly true

I can't see passenger seat module it in the ISTA tree of modules.
When I put my original passenger seat back in, it works, but the car is not seeing the seat module. But I'm not getting errors where it can't find the heater or SRS.

My original passenger seat didn't have lumbar, adjustable bolsters or memory; just heat. Drivers seat had all features.

The OEM passenger seat in your i4 has a switch, not a controller. No controller means that there are no K-CAN wires in the OEM seat connector in the passenger side. No K-CAN wires means that no coding can be done on the passenger M Seat to re-enable passenger occupancy sensor, and clear the airbag error.

• Add 2 wires: K-CAN +/- (pin 5, pin 6) to passenger controller - enable SM2 passenger controller in BimmerUtility. Either run wires from BDC, or split K-CAN wires from driver seat connector (pin 5 and pin 6) to passenger seat connector (yellow).
• VO Code 711 (M Seats), remove 481(Sport seats) via BimmerUtility
• Enable occupancy sensor on new passenger controller (SM2) via ISTA (clear any airbag error)

[techwhiz1]

Originally Posted by Technic

The OEM passenger seat in your i4 has a switch, not a controller. No controller means that there are no K-CAN wires in the OEM seat connector in the passenger side. No K-CAN wires means that no coding can be done on the passenger M Seat to re-enable passenger occupancy sensor, and clear the airbag error.

Add 2 wires: K-CAN +/- (pin 5, pin 6) to passenger controller - enable SM2 passenger controller in BimmerUtility. Either run wires from BDC, or split K-CAN wires from driver seat connector (pin 5 and pin 6) to passenger seat connector (yellow).
VO Code 711 (M Seats), remove 481(Sport seats) via BimmerUtility
Enable occupancy sensor on new passenger controller (SM2) via ISTA (clear any airbag error)

Okay, that helps me understand why it can't find the controller. Is that also why the seat doesn't work at all?

Looking at the plug on the seat which are wires 5,6.

I'll add the wires tomorrow when I get home.

Thanks

[Technic]

Originally Posted by techwhiz1

Okay, that helps me understand why it can't find the controller. Is that also why the seat doesn't work at all?

Looking at the plug on the seat which are wires 5,6.

I'll add the wires tomorrow when I get home.

Thanks

Seat (Yellow - X12*1B) connector

[techwhiz1]

Thanks!

The wires were absolutely missing on the passenger side connector.

I pulled the wires from the seat connector.
I ran the wires under the console.
Now I'm working on how to wire into the drivers seat.

Hopefully done tomorrow.

You have no idea how frustrated I was.

[techwhiz1]

Current update.

Wired seats together.
Was able to VO code seats.

The lumbar and bolsters do not work?
More wires?
Not a huge issue. I'll have to deflate the lumbar because it came inflated..

Tried adding lumbar for passenger in the VO, but nothing.

Anyway, installing ISTA to try to remove restraint errors.

[Technic]

Pin 15 of yellow connector should be wired to pin 7 of controller in M Seats. Currently, pin 15 is wired to somewhere else.

Originally Posted by techwhiz1

Current update.

Wired seats together.
Was able to VO code seats.

The lumbar and bolsters do not work?
More wires?
Not a huge issue. I'll have to deflate the lumbar because it came inflated..

Tried adding lumbar for passenger in the VO, but nothing.

Anyway, installing ISTA to try to remove restraint errors.

[techwhiz1]

Originally Posted by Technic

Pin 15 of yellow connector should be wired to pin 7 of controller in M Seats. Currently, pin 15 is wired to somewhere else.

I'm a bit confused pin15 of yellow connector is clear.

Pin 7 of controller is not clear? Not sure where pin 7 on controller is.

Also I can't clear the seat position sensor error. Is the seat position sensor to be removed and fitted to the M passenger seat?
Or is that part of the additional wiring?

Trying to get that last bit sorted so I don't have to pull the seat anymore but a single time.


Also tried to PM you and your box is full.
I'd like to pay you for your time to get this finished up. I think I'm close but have a few more questions.

[Technic]

I cannot receive PM in this forum.

The seat occupancy sensor needs to be re-enabled - go to ISTA - highlight airbag error - look for the repair plan - follow the prompts. You may need a second person in the car, or follow the steps while sitting on passenger seat.

This will clear the airbag error unless there is something really wrong with the seat sensor.

Originally Posted by techwhiz1

I'm a bit confused pin15 of yellow connector is clear.

Pin 7 of controller is not clear? Not sure where pin 7 on controller is.

Also I can't clear the seat position sensor error. Is the seat position sensor to be removed and fitted to the M passenger seat?
Or is that part of the additional wiring?

Trying to get that last bit sorted so I don't have to pull the seat anymore but a single time.


Also tried to PM you and your box is full.
I'd like to pay you for your time to get this finished up. I think I'm close but have a few more questions.

[techwhiz1]

Originally Posted by Technic

I cannot receive PM in this forum.

The seat occupancy sensor needs to be re-enabled - go to ISTA - highlight airbag error - look for the repair plan - follow the prompts. You may need a second person in the car, or follow the steps while sitting on passenger seat.

This will clear the airbag error unless there is something really wrong with the seat sensor.

No the seat occupancy sensor replacement went great. That code cleared.

What is not working is the position sensor or how the position sensor works on the new seat. I noticed that my new seat didn't have a gray sub connector in the yellow plug. That gray connector goes to the position sensor which is some type of hall effect sensor.

The position sensor is too itor the position of the seat to decide how to deploy the airbag.

No issues moving it, but it's strange that the new seat didn't have a position sensor or that function is not somewhere in the module.

Also not really sure the pin 7 thing. I'm not sure what pin 7 on the module you are talking about.

Adding and moving wires isn't an issue. Just not sure what to do.

So if you can tell me what you are talking about pin 7 on the controller I'll wire that to pin 15 in the yellow plug.

Also any insight on the position sensor would be great.

Hate to be a bother, but I'm more than willing to pay you for your time if we can connect directly some way.

[Technic]

Is this an error showing up in ISTA? If so then try performing a repair plan to see if this controller has another way of implementing this sensor.

Pin 7 is only applicable if you want to power the ///M badges - either run a line from BDC (OEM), or use the 12V line from the underseat illumination (always on while driving).

Originally Posted by techwhiz1

No the seat occupancy sensor replacement went great. That code cleared.

What is not working is the position sensor or how the position sensor works on the new seat. I noticed that my new seat didn't have a gray sub connector in the yellow plug. That gray connector goes to the position sensor which is some type of hall effect sensor.

The position sensor is too itor the position of the seat to decide how to deploy the airbag.

No issues moving it, but it's strange that the new seat didn't have a position sensor or that function is not somewhere in the module.

Also not really sure the pin 7 thing. I'm not sure what pin 7 on the module you are talking about.

Adding and moving wires isn't an issue. Just not sure what to do.

So if you can tell me what you are talking about pin 7 on the controller I'll wire that to pin 15 in the yellow plug.

Also any insight on the position sensor would be great.

Hate to be a bother, but I'm more than willing to pay you for your time if we can connect directly some way.

[techwhiz1]

Originally Posted by Technic

Is this an error showing up in ISTA? If so then try performing a repair plan to see if this controller has another way of implementing this sensor.

Pin 7 is only applicable if you want to power the ///M badges - either run a line from BDC (OEM), or use the 12V line from the underseat illumination (always on while driving).

Oh, yeah, I don't really care about the lights in the badges.

There is an error and I tried a repair plan but it doesn't find the position sensor. It says open circuit.

Also the lumbar and bolsters aren't working on the passenger seat but fine on the driver seat.

But I'll go ahead and move the sensor and double check all connection on the module.

Thanks again.

[Technic]

No wire at pin 15 of yellow connector?

Originally Posted by techwhiz1

Oh, yeah, I don't really care about the lights in the badges.

There is an error and I tried a repair plan but it doesn't find the position sensor. It says open circuit.

Also the lumbar and bolsters aren't working on the passenger seat but fine on the driver seat.

But I'll go ahead and move the sensor and double check all connection on the module.

Thanks again.