GM enhanced PID List?

[AndyL]

Frustrated at the lack of shareware/freeware OBD2 Diesel specific scantool software I have decided to write my own. The hardware and general comm software was easy, now I am stuck on the PID codes for the GM diesel specific senors/parameters.

Anyone have a list?

Andy

[a5150nut]

Andy,
I take it your not talking about DTC error codes?

a5150nut@hotmail.com

[AndyL]

Originally posted by a5150nut:
Andy,
I take it your not talking about DTC error codes?

a5150nut@hotmail.com Actually no. There is a special hex character string that is sent to the vehicle PCM that will instruct it to sent back its value.

For example:

PID "0C" asks the PCM to send Engine RPM.
PID "0D" asks the PCM to send Vehicle Speed.

The above PIDs are GM generic, I am looking for the Diesel specific codes. Reading boost, stored timing offset etc.

Andy

[Dimsdale]

I did a Google search on PIDs and came up with this: http://216.239.59.104/search?q=cache:iidB21xMWiwJ:pcm.dxsoftware.com/vpw.htm+gm+pid+code&hl=en&ie=UTF-8.

No idea how to interpret it or if it is what you are looking for.

A company called Jendham purportedly publishes expensive manuals with this kind of information, but I have no inforation to support this.

Maybe there is a GM tech out there that can help. GMCTD? Charlie Petersen?

[gmctd]

Dimsdale, you done good! Appears to be for gassers, but it's good start.

FYI, slagona posted an address sevaral months back for OBD specs from the USGOV, iirc.

Anyone else?

[slagona]

About 3-4 times a year, I renew my quest for an inexpensive OBDII Scanner that will allow me to at least view ALL parameters - OR - the info which would allow me to write the software. After almost two years of searching (not very enthusiastically), I have not found anything acceptable.

Sometime in the last month, I came across:

http://www.scantool.net/index.htm

For about $65-75, you can get the hardware (Search ElmScan on ebay motors). Software is a free download from scantool.net.

Problem is that you can't get the GM extended, or enhanced, parameters with this software (which is what really interests me - ok, so IAT is available and that does interest me...). There is a forum on scantool.net in which several people have requested these parameters - but all have come up empty. The PID list mentioned in previous replies is also referenced in this forum.

Someone in that forum has offered his version that he has developed which claims to have GM extended parameters:

http://www.scantool.net/forum/index.php?board=2;action=display;threadid=475;star t=msg2080#msg2080

Haven't looked into this yet - but it would be a good place to start if one were interested..... You could use your existing hardware with his software to see what's there......

Problem I see is how to intrepret the results. You make a request - get a result - and interpret it by using what scale? 0.15 volts equals how much boost on the turbo?. I haven't looked in my GM Helm manuals yet to see if this info is in there - I don't think it is..... (You can see how enthusiastic I've been about this for the last few years).

Hope this helps in some way. Reading that forum might give you other leads.

The doc that gmctd refered to may have been:

ftp://download.intel.com/design/intarch/papers/j1850_wp.pdf

Good luck with the software development.

--Scott

[ 12-29-2003, 01:43 PM: Message edited by: slagona ]

[AndyL]

Scott,

When I am finished (assuming I can find the PID list) there will be an inexpensive scantool available.

[rjschoolcraft]

The voltage scales for each sensor and parameter are listed in the Helm Manuals.

[ChevyDooley]

Autozone sells a scan tool here for $31.00. Works great.

[slagona]

We're really talking about more than a Scantool here. The inexpensive scantools read the Diagnostic Codes - and only the codes. That is readily available. We are looking for a package that will view ALL of the info available, items such as Boost Pressure, Intake Air Temp, TDC Offset, ..... and display the actual values for these items.

With a package such as this, we could eliminate all gauges (or duplicate and verify) except for EGT and Fuel Pressure (between lift pump and Injection pump). I'm already up to 5 gauges, and would like more - this would allow me to monitor the "sensor of the week" without adding gauges. It would also aid to diagnostics - as we are really heading towards a GM TechII type system.

--Scott