Scangauge Boost Gauge and General XGauge Coding info

[seftonm]

With help from CarlD and 2way on the cleanmpg forums I now have an XGauge that comes close to showing the gauge pressure of the MAP (turbo boost) instead of the absolute pressure (atmosphere plus boost). The coding is as follows:

TXD: 68 6A F1 01 0B
-or-
TXD: 07 E0 01 0B for CAN-bus vehicles. The new TDI apparently won't report MAP and therefore this won't work.
RXF: 04 41 85 0B 00 00
RXD: 28 08
MTH: 00 91 00 64 FF 71

This will get the absolute MAP pressure, convert it to PSI, and subtract a constant, which in my case is the average atmospheric pressure in Brandon. Subtracting the average atmospheric pressure gives a close idea of how much boost the turbo is making. If a drive has large changes in elevation or pressure the gauge can be out by a few PSI.

The last four characters in the MTH field are an addition. To subtract, you must add the 2's complement of the number you wish to subtract. In this case, the result is being divided by 10, so the number being subtracted must also be multiplied by 10. For example:
I want to subtract 14.3 PSI. 14.3 * 10 = 143 = 008F in hex. 2's complement of 008F is FF71. The last 4 characters in the MTH field are therefore FF71 in my case.

Of course, pressure varies with elevation so you may need to subtract a different value. Here are the 2's complement representations of common values for pressure:
12.0 -- FF88
12.1 -- FF87
12.2 -- FF86
12.3 -- FF85
12.4 -- FF84
12.5 -- FF83
12.6 -- FF82
12.7 -- FF81
12.8 -- FF80
12.9 -- FF7F
13.0 -- FF7E
13.1 -- FF7D
13.2 -- FF7C
13.3 -- FF7B
13.4 -- FF7A
13.5 -- FF79
13.6 -- FF78
13.7 -- FF77
13.8 -- FF76
13.9 -- FF75
14.0 -- FF74
14.1 -- FF73
14.2 -- FF72
14.3 -- FF71
14.4 -- FF70
14.5 -- FF6F
14.6 -- FF6E
14.7 -- FF6D
14.8 -- FF6C
14.9 -- FF6B
15.0 -- FF6A

Here are two sites to computer atmospheric pressure based on elevation, courtesy of Bayou_Flyer and Mrrogers1:
http://www.turblex.com/altitude/index.cfm
http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=214

I was also given help for XGauge programming and OBD-II PID's. The programming guide is at http://pics.tdiclub.com/data/500/XGauge_Coding.pdf
and OBD PID's are at http://en.wikipedia.org/wiki/OBD-II_PIDs


Other useful codes: (PM me and I'll add to the list)

Water temperature for newer vehicles where the default water temperature gauge won't work:
TXD: 07DF0167
RXF: 04410567
RXD: 3008
MTH: 00090005FFD8 (or 00010001FFD8 if you prefer celcius)
NAM: WTR

 

[Reichard]

Excellent! MAny thanks for the writeup! Took about two minutes to add.

Now if ony I could get a torque xgauge displayed. I have logs of mine from my vagcom and it would be a great addition.

 

[MPLSTDI]

Great tested and works great, only thing is if we could give the map data to update faster. It's a little slow

 

[seftonm]

Have you tried increasing the ScanGauge update speed?

 

[weasel]

I was hoping someone would come up with this. As soon as I added distance to empty as an x-gauge, doing the same for the map was the first thing I though of. Very shortly, I am going to put my coat on and do this.

 

[weasel]

Just came in from the cold. Seems to work fine. Didn't take it for a drive yet, but I did start it. Slight negative boost at idle ( .6psi and I expected that ). Will report if anything funky, but I expect not. Thanks again !

 

[Reichard]

Have you tried increasing the ScanGauge update speed?

I can't notice a difference in the update speed settings at all.

 

[weasel]

I don't think that will make a difference anyway. The ECM only samples so fast.

 

[seftonm]

I thought the Mk5's used a CAN bus, which is often fast enough to use the fast update speed. If there is no difference, you should probably slow the update speed back down to avoid possible errors.

 

[TheDieselFamily]

Seftonm, your original post sounds like you did the XGage upgrade your self. Is this the case? If so can you share how you did it, or point those of us with the pre-XGage somehwere to help?

The ScanGage II web site says you have to send the unit back for the upgrade. I do not want to go without the ScanGage, especailly when I am pulling a trailer.

Thanks...

 

[MPLSTDI]

Have you tried increasing the ScanGauge update speed?

Isn't there a way to do just one, I don't want everything since the instant MPG jumps too fast than.

 

[MPLSTDI]

Seftonm, your original post sounds like you did the XGage upgrade your self. Is this the case? If so can you share how you did it, or point those of us with the pre-XGage somehwere to help?

The ScanGage II web site says you have to send the unit back for the upgrade. I do not want to go without the ScanGage, especailly when I am pulling a trailer.

Thanks...

You can add it yourself if you have a more current verison (with xguage) if not you need to send it in and they will update it.

 

[seftonm]

You can add it yourself if you have a more current verison (with xguage) if not you need to send it in and they will update it.

That's right, my ScanGauge came with XGauge already installed. All I did was use the XGauge feature to create a boost gauge.

MPLSTDI, there is not a way that I know of to change the update speed of individual gauges. I will let you know if I find anything.

 

[MPLSTDI]

That's right, my ScanGauge came with XGauge already installed. All I did was use the XGauge feature to create a boost gauge.

MPLSTDI, there is not a way that I know of to change the update speed of individual gauges. I will let you know if I find anything.

Thanks

 

[Honeydew]

hey seftonm- if you can figure out the coding for a fuel temperature xgauge lots of members would be grateful!

 

[cboman]

Hi guys!

So You all read turbo boost in PSI's? Here in Europe we use BAR's. Can this code be translated so that it shows bars? Thanks!

Yours,

Christian

 

[seftonm]

Hi guys!

So You all read turbo boost in PSI's? Here in Europe we use BAR's. Can this code be translated so that it shows bars? Thanks!

Yours,

Christian

Hi Christian, all that should be required is to change the MTH field. Try this and let me know what happens:

TXD: 68 6A F1 01 0B
RXF: 04 41 85 0B 00 00
RXD: 28 08
MTH: 00 0A 00 64 FF F6

Once again, you may want to subtract a different value than FFF6 based on the expected air pressure. Here's common values:

FF F4 - 1.2 bar
FF F5 - 1.1 bar
FF F6 - 1.0 bar
FF F5 - 0.9 bar
FF F4 - 0.8 bar

Hope that works,
Mike

 

[EnthymematisHabilis]

I just got my upgraded SGII back today after exactly 1 week from mailing it. Actually I think they just send you a new one once they receive your old one.

For the turbo boost pressure X-Gauge, you can see what your local atmospheric pressure is by looking at the MAP gauge with your engine off/idling (pretty close, either way). I did wonder if there's a way to use the atmospheric pressure reading from the sensor in the EDC as the base instead of a static value, though.

-David

 

[Jetta2001TDI]

Has anyone been able to program EGT as an xgauge? It would seem to be a perfect compliment to the boost gauge.

 

[Honeydew]

Has anyone been able to program EGT as an xgauge? It would seem to be a perfect compliment to the boost gauge.

Scangauge can only display info detected by the ECU via OEM sensors. There are no factory EGT sensors in the TDI so therefore EGT xgauge is impossible. Boost xgauge works because there is a Manifold Air Pressure sensor.

 

[Jetta2001TDI]

Scangauge can only display info detected by the ECU via OEM sensors. There are no factory EGT sensors in the TDI so therefore EGT xgauge is impossible. Boost xgauge works because there is a Manifold Air Pressure sensor.

That's true, however VAG COM displays an EGT value somehow, and I was wondering if it is possible to send a command to the ECU to return the EGT.

But again this value may not be returned by the ECU, but rather calculated by VAG COM based on other parameters.

 

[vw4life]

Hi Guys,

I to am very intersted in an EGT scangauge xgauge, as, Passat TDI's with BWH engine do have a stock EGT sensor. I have done a fair bit of asking about this and have been repeatedly told no, its not going to work (that is unless scangauge can emulate VAGCOM somehow...)

link 1: http://forums.tdiclub.com/showthread.php?t=193539


If someone figures this out I will buy scangauge right away (scangauge are you listening?)

 

[Honeydew]

Hi Guys,

I to am very intersted in an EGT scangauge xgauge, as, Passat TDI's with BWH engine do have a stock EGT sensor. I have done a fair bit of asking about this and have been repeatedly told no, its not going to work (that is unless scangauge can emulate VAGCOM somehow...)

link 1: http://forums.tdiclub.com/showthread.php?t=193539


If someone figures this out I will buy scangauge right away (scangauge are you listening?)

Have you contacted Linear Logic directly about this? I have found them to be very responsive and maybe you can work with them to figure out the coding.

 

[vw4life]

Several months ago I asked them but they indicated it wasn't likely. I will try again now...

 

[RyansToy]

Awesome Job! Worked like a charm

 

[Lex4TDI4Life]

has anyone tried pulling the injection quantity into the gauges?

 

[Bayou_Flyer]

I found a helpful link. Scroll to the bottom of the page and input your local altitude above sea level. Plug in your numbers and it will convert that to an atmospheric pressure. Something quick and easy from which to start.

http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=214

 

[Mrrogers1]

Another tool

Here is another tool as well http://www.turblex.com/altitude/index.cfm

 

[milehighassassin]

Has anyone tried this on a 1.8t?

I have a friend who bought one of these and the SG will not show ANY MAP readings.

Thoughts, suggestions?

 

[K5ING]

Thanks seftonm. Works great and was simple to do. Just put the boost xgauge in, along with the average (today) mpg xgauge. Now I'm set.