Converting an MSS54/HP into an MSS54HP CSL (H-bridge)

[Jeppe1976]

Just read the pressure via Tool32 to see if the value is valid related to your location.

I would guess the Barometric pressure is the one being read from DME? because if i disconnect the external one nothing changes in the reading. And on my location it is: Barometric Pressure: 100KPa

I used my Autel diagnostic tool "Live data" to get the reading

[S54B32]

Hi,

How do i know if the onboard pressure sensor is changed? And what would happen if i change the Pressure scale like you mention below? Is there any risk the DME dies?


"Also the onboard pressure sensor is different. You can either install one with the same specs as the MSS54HPs (MPXA6115A or MPXAZ6115A), or you can change the pressure scale (at 0xC476, change "D3 1C 12" to "C2 5F 03"). "

Just read the pressure via Tool32 to see if the value is valid related to your location.

[Jeppe1976]

Hi,

How do i know if the onboard pressure sensor is changed? And what would happen if i change the Pressure scale like you mention below? Is there any risk the DME dies?


"Also the onboard pressure sensor is different. You can either install one with the same specs as the MSS54HPs (MPXA6115A or MPXAZ6115A), or you can change the pressure scale (at 0xC476, change "D3 1C 12" to "C2 5F 03"). "

Originally posted by Terra on M3Forum:

Might as well post this



Red resistors are the ones you definitely have to change if you want to use the MAP sensor. 7.15 kΩ resistors seem to do the trick there. The yellow ones are also different (10 kΩ on the MSS54HP, 1 kΩ on the non-HP), but they don't appear to effect anything.

Also the onboard pressure sensor is different. You can either install one with the same specs as the MSS54HPs (MPXA6115A or MPXAZ6115A), or you can change the pressure scale (at 0xC476, change "D3 1C 12" to "C2 5F 03"). Sorry, forgot to mention that in the emails to you NZ

One thing I want to make clear is that this is still fairly experimental. You're modifying the DME in ways BMW never intended. While I've done a fair bit of testing, it's impossible for me to test all scenarios.

[simonnim]

This is pretty simple stuff, just gotta pay for a hot smog every couple of years.

Unless you know someone for cheap.

[nextelbuddy]

What happens if you switch to HP non-CSL software?

Haven't tried that yet since I need CSL software for my setup. May try that later just to see what happens

[EthanolTurbo]

This is what I'm worried about too...otherwise I'd have swapped to airbox and 200 cell race cats etc. I still want to drive it on the road and have no issues selling it.

This is pretty simple stuff, just gotta pay for a hot smog every couple of years.

[Slideways]

Well I can confirm for me that hp converted DME with CSL software also shows unavailable for emissions monitors readiness

Probably won't pass emissions here in Georgia like that.

Other than that, the DME works fine and starts my S54 no problem

What happens if you switch to HP non-CSL software?

[simonnim]

This is what I'm worried about too...otherwise I'd have swapped to airbox and 200 cell race cats etc. I still want to drive it on the road and have no issues selling it.

[nextelbuddy]

That's interesting. I'll definitely have to try that and see if I see a difference with readiness on CSL versus non-CSL on HP converted DME.

Well I can confirm for me that hp converted DME with CSL software also shows unavailable for emissions monitors readiness

Probably won't pass emissions here in Georgia like that.

Other than that, the DME works fine and starts my S54 no problem

[nextelbuddy]

A forum member here with a non-HP to HP conversion went back to standard software from CSL and didn't have any issues with readiness.

That's interesting. I'll definitely have to try that and see if I see a difference with readiness on CSL versus non-CSL on HP converted DME.

[Slideways]

So just curious, at this point we have this thread with tons of amazing information that allows people to convert standard MS54 DMEs into MS54 HP DMEs

Are we at the point now where we can almost officially say that conversion of this nature is confirmed to break emissions readiness monitors?

Reading from this thread here it looks like two or three people confirmed they all had the same issue after converting the standard MS54 to HP and their emissions monitors just seen not available and to pass emissions they had to purchase another stock untouched DME just to pass emissions.

https://nam3forum.com/forums/forum/m...ions-monitors/


I have three standard MSS54 DMEs that I converted to HP and I planned on selling them but I'm not going to sell them now because if they can't pass emissions they're useless to people that have daily drivers So it looks like you can really only be used by maybe E30 and E36 people with S54 swaps or E46 m3s that live in states/counties that don't do emissions checks.

A forum member here with a non-HP to HP conversion went back to standard software from CSL and didn't have any issues with readiness.

[nextelbuddy]

So just curious, at this point we have this thread with tons of amazing information that allows people to convert standard MS54 DMEs into MS54 HP DMEs

Are we at the point now where we can almost officially say that conversion of this nature is confirmed to break emissions readiness monitors?

Reading from this thread below, it looks like two or three people confirmed they all had the same issue after converting the standard MSS54 to HP and their emissions monitors just say not available and to pass emissions they had to purchase another stock untouched DME just to pass emissions.

https://nam3forum.com/forums/forum/m...ions-monitors/


I have three standard MSS54 DMEs that I converted to HP and I planned on selling them but I'm not going to sell them now because if they can't pass emissions they're useless to people that have daily drivers So it looks like you can really only be used by maybe E30 and E36 people with S54 swaps or E46 m3s that live in states/counties that don't do emissions checks.

[sapote]

Thanks.
So it’s the system 5v for most of the chips including the processor and 2 Flash memory chips. I thought the board needs a 5v switching regulator and surprised to see it has a linear one.

[heinzboehmer]

Anyone with the DME box opened, can you try to read the part number print on the chip in red circle in pic below? The DME I try to fix, the chip has no marking to read.
Thanks.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/231791-help-identify-component-on-m3-dme-circuit-board?p=233161#post233161

[sapote]

Anyone with the DME box opened, can you try to read the part number print on the chip in red circle in pic below? The DME I try to fix, the chip has no marking to read.
Thanks.