[BandWagon]

Hi guys!
I am in the middle of a n54 manual swap in to a e91 and I ran in to the differences in the DSC systems between Rwd and Awd.

My concerns are why there are differences in the DCS systems and the effects this can have on a car when parts are swapped.

My information I found is from my own efforts, Realoem, and the Bentley manual. I am working on getting the computer-based manuals now maybe those have some missing key information.

To start this off the whole DSC system seems to be created by ATE. (DSC module, DSC sensor, and fluid)

First the differences:
• Different DSC modals with incapable plugs
• Rwd DSC Module has 3 additional wires not discussed in the Bentley manual
• Different DSC Sensors (Rwd ATE, AWD Bosch)
• Brake lines

This seems to be a very expensive and complex difference between these two systems

This difference in systems seems to across all Rwd and Awd bmw's of this generation.
I also found that only the Rwd vs Awd changes this system, not different engines or manual vs auto trans. EX RWD auto n52 and manual n54 cars have the same DSC system.
E90, e92 M3s also have a different DSC system. this tells me that this is a critical system that needs to follow the drive train.

I don’t have performance metrics to prove what system is better but after completely removing both my awd system and rwd system from my donor. The Rwd system over all seems more advanced. The Rwd DSC Sensor made by ATE has a 6 pin out while the Awd Bosche DSC sensor only has 4 pins. Even the RWD DSC module is slightly larger and heavier this could be due to a stronger pump. I haven’t been able to track down the fuses yet but I would not be surprised if the fuse was bigger on the Rwd system.

Anything beyond this is pure speculation.

My bet is that when swapping from Awd to Rwd if you don’t change the full DSC system over you could experience unpredictable traction control problems, lazy reactions from the DSC, or at worse improper corrections during a spin out.

Maybe this all has no real effect on the cars, but it sure seems like a lot of effort on bmw’s part to make such different systems if they didn’t matter.
I would recommend changing the DSC system along with the Drive-train

I would love to hear any thoughts or experiences on this.

TLDR: Swap your DSC when going from Rwd to Awd

[charlie_m]

I don't know any of the details, but just thinking about it, this makes sense. DSC is a bunch of complicated algorithms with inputs and outputs, and these inputs / outputs are different between RWD and AWD. IE, front tires can apply tractive force as well as braking force and torque split between front / rear is an output of the DSC algorithm, that's obviously not there in RWD.

I would not read too much into the capabilities based on size of the units or fuse rating. More likely one manufacturer had a well-developed AWD DSC system and the other one just did RWD.

I'll post back if I find an background info on this. There is some good background training info here; Nothing jumped out at me, but there's a lot to go through:
https://www.e90post.com/forums/showthread.php?t=1360573

[mad1stgen]

You need to wire in the corresponding dsc module/sensors. Otherwise you'll never be able to align dsc with dme/cas set, and dme will be stuck in limp limited boost mode. It's not an IF, it's a must.

[BandWagon]

mad1stgen I agree on needed the correct DSC module but I have seen very little information on the DSC when a swap like this is done.

Unless is it going unsaid but I have found no one talking about DSC problems when doing a swap, even less on the DSC sensor. this is why i said maybe its not a problem with the CAS and DCM but I couldn’t see the system working correctly with out the full corresponding DSC system being swapped

I figured I would at least start the convo so that this information can be found.

I can go in to way more detail on the things I found on this, but that is mostly proving that the systems are different and largely redundant.

[TyroneShoelaces]

I'm in the middle of my swap from AWD to RWD. I pulled the DSC (ABS?) from my manual 335 donor as it's off to the scrappers this weekend but I'll have another RWD car as a spare to pull parts from if necessary. (auto rwd dct E92)

Maybe you're ahead of me as I just hung my motor and am starting the fab of the mount similar to what Redshifts done, and swapping diffs etc and putting coding off to the end so maybe I'll get lucky and you'll have it sorted out. Not many go AWD to RWD.

Are you talking about using wheel speed sensors from the awd car too? Isn't the whole reluctor ring setup different on the front knuckle?

The guys in Michigan know what they're doing with this. Do whatever they say.

[BandWagon]

My post is mostly about the different DSC module and DSC sensor from the rwd to awd

Note: the DCS sensor in under the driver seat and the seat must be removed.

if you have the Bentley manual the wiring isnt to hard to sort out when you repin the RWD dcs connector to the e91 you will be missing 3 wires and will need bigger connectors on the red blue power line and brown ground line.

Originally Posted by TyroneShoelaces

I'm in the middle of my swap from
The guys in Michigan know what they're doing with this. Do whatever they say.

I am not sure what you mean by this?

[TyroneShoelaces]

Originally Posted by BandWagon

My post is mostly about the different DSC module and DSC sensor from the rwd to awd

Note: the DCS sensor in under the driver seat and the seat must be removed.

if you have the Bentley manual the wiring isnt to hard to sort out when you repin the RWD dcs connector to the e91 you will be missing 3 wires and will need bigger connectors on the red blue power line and brown ground line.





I am not sure what you mean by this?

I have a bentley on the way so I'll have to investigate further. Mad1Stgen in MI if you look back has some history on doing the swap, whatever he posts is from experience.

[TyroneShoelaces]

Bandwagon, did you get your DSC swap done? BimmerBarn on youtube just did this DSC swap but didn't do anything with the sensor under the seat. He used the rwd plug and dsc module.

I realize now I should have swapped my brake lines before I put in the engine but I needed to get it out of the middle of the garage

[BandWagon]

I was able to complete the Swap I haven’t changed my under seat sensor yet, my main goal right now is getting the car back on the road then I will update to the correct sensor.

I had come other problems with the DSC not communicating but I tracked down 2 mismatched wires that are the same color on the DSC connector. Also, your clutch and brake wires need to be done otherwise you can’t get into acc. mode and the dsc module won’t turn on. Also, you DO NOT NEED Auto harness plugged in and There is no magic Ground loop.

Proof: my car is happily running with my auto harness siting on my desk.

[TyroneShoelaces]

Originally Posted by BandWagon

I was able to complete the Swap I haven’t changed my under seat sensor yet, my main goal right now is getting the car back on the road then I will update to the correct sensor.

I had come other problems with the DSC not communicating but I tracked down 2 mismatched wires that are the same color on the DSC connector. Also, your clutch and brake wires need to be done otherwise you can’t get into acc. mode and the dsc module won’t turn on. Also, you DO NOT NEED Auto harness plugged in and There is no magic Ground loop.

Proof: my car is happily running with my auto harness siting on my desk.

The dsc yaw sensor under the driver seat on my car was not compatible awd vs rwd. I left my awd one as the connector was different.

Transfer case module under the passenger seat needs unplugged or I believe it will always have a 4x4 error.

[BandWagon]

You will have to rewire the RWD connector in.

[Jasmeleg]

I am sorry to bring up an old thread but I would like to pick your brain BandWagon. Did you end up swapping to the RWD DSC sensor (Yaw sensor) or keeping the AWD sensor in place? Looking at the wiring diagrams the X18303 on the RWD connector has 4 points to the DSC sensor (Canbus and power) and the X1746 has 3 wires to the AWD DSC sensor. The AWD sensor is grounded to the chassis not the DSC module which I can't see causing an issue.

It looks like although the RWD sensor has a 6 pin connector only 4 pins are populated?

I would also assume although the you can wire up the AWD sensor to the RWD DSC module, the CAN messages will be different between the two. If they are the same then it will probably not throw an error but could cause issues because it is calibrated to an AWD chassis not RWD.

I say all these because I to have a wrecked E91 in my driveway and am sourcing a donor E90 rwd 335 as I type...

[TyroneShoelaces]

Originally Posted by Jasmeleg

I am sorry to bring up an old thread but I would like to pick your brain BandWagon. Did you end up swapping to the RWD DSC sensor (Yaw sensor) or keeping the AWD sensor in place? Looking at the wiring diagrams the X18303 on the RWD connector has 4 points to the DSC sensor (Canbus and power) and the X1746 has 3 wires to the AWD DSC sensor. The AWD sensor is grounded to the chassis not the DSC module which I can't see causing an issue.

It looks like although the RWD sensor has a 6 pin connector only 4 pins are populated?

I would also assume although the you can wire up the AWD sensor to the RWD DSC module, the CAN messages will be different between the two. If they are the same then it will probably not throw an error but could cause issues because it is calibrated to an AWD chassis not RWD.

I say all these because I to have a wrecked E91 in my driveway and am sourcing a donor E90 rwd 335 as I type...

FWIW not sure if you're still wondering but I just finally swapped my yaw sensor under the seat last night from awd to rwd by re-pinning it. Cleared up another dash light and allowed me to do a steering sensor alignment.