More PIDs for Torque App

In another thread there has been a handful of comments regarding Torque Pro and transmission parameters. Thought I would toss out a couple of things I wonder about here.

Torque Pro has their set of extended parameters that I have long surmised initially came from user submissions. What vehicles these users were testing on we will never know. So some PIDs work on our platform and some do not. For trans fluid temp there are 2 where the only difference is the header (one is for CANBUS vehicles).

Some appear to work but how reliable are they?

Take the PID for input shaft speed,... according to wiring diagrams my 2002 has no input shaft speed sensor so what is the source of this value??

Similarly there is the PID for TCC Slip... With no input shaft speed sensor how can this be determined and differentiated from some other component slippage??

Do you know what PCM your vehicle is using? I really don't know doodly squat about this PCM vs that PCM but if it were the same as one I have there is at least some expectation that PIDs just might be the same.

My Trailblazer has no tow/haul mode (don't know if any of them do?) but my Yukon does.

This discussion of Tow/Haul mode... I had to go back in this thread to even see what I had been doing as with many such things I get into it for a time then move on and forget about it! So I see that I never did come to any conclusions about this 1973 PIDs bit 0 validity.

@jawhnny what response were you seeing for the 1973 PID? Did you try the PID test button in the equation editor and see the complete response or were you only looking at a Torque Pro dashboard display?
2001 truck 5.3 4l60e pid 1973 works as a tow haul indicator. Fully tested.
However I understand it may not for others.
My Jimmy is using a P59 I believe
Mine never had a Tow/Haul button either but I did see it say it would use that shift table if commanded by the TCCM if it if shifted into 4lo.
I also saw I could enable a setting in TunerPro to enable it by a momentary ground to pin 71 on the PCM instead of just the TCCM data bus signal.


Works like a charm now, thank you!!
To me it seems it just switches to tell you its NOT in normal trans mode.
When I looked through TunerPro, it showed 4 tranny modes. Normal, performance/tow, manual and WOT modes. If any of these other modes are enabled, it seems to trigger this.

Works perfect to tell me if my Tow/Haul button works when I push it though.
There are 5 modes in the tables.
1 Normal
2 (tow haul trucks)/competition
3 hot mode triggered by pcm
4 another one I forget
5 unused mode

Hot mode is to cool overheated trans
 

jawhnny

New Member
Take the PID for input shaft speed,... according to wiring diagrams my 2002 has no input shaft speed sensor so what is the source of this value??

Similarly there is the PID for TCC Slip... With no input shaft speed sensor how can this be determined and differentiated from some other component slippage??
Maybe the PCM or defined Torque PIDs cheat by looking at other values?
Im assuming here but could it not just use the crankshaft speed or engine rpm, use that as a input speed of the trans, and compare it to the output speed even just using the vehicle speed sensor? Then tcc slip speed is just the difference?

I actually do use slip speed all the time to watch my PWM lockup and think its pretty accurate, 20-40 rpm difference when accelerating on highway in 3rd which is what I think it should be.
 
Maybe the PCM or defined Torque PIDs cheat by looking at other values?
Im assuming here but could it not just use the crankshaft speed or engine rpm, use that as a input speed of the trans, and compare it to the output speed even just using the vehicle speed sensor? Then tcc slip speed is just the difference?

I actually do use slip speed all the time to watch my PWM lockup and think its pretty accurate, 20-40 rpm difference when accelerating on highway in 3rd which is what I think it should be.
This is probably what they do. Doesn't help figuring out if you're trans is slipping. They may have parameters to indicate high slippage, who knows?
 

Dawezel1

New Member
Hello I'm having troubles with the PID'S.. Ive seen three different ones for gm oil psi and none of them work for me I have torque pro and engine /PCM is from a 2003 GMC 2500hd oil psi is only gauge I can't get any help would be great thanks
 

TollKeeper

Gold Supporter
I think @TJBaker57 is the man you want to talk to!
 
OP
TJBaker57

TJBaker57

Well-Known Member
Hello I'm having troubles with the PID'S.. Ive seen three different ones for gm oil psi and none of them work for me I have torque pro and engine /PCM is from a 2003 GMC 2500hd oil psi is only gauge I can't get any help would be great thanks

The thing to do here is look at your wiring diagram for the vehicle. That will show where the oil pressure sensor is wired to. If it goes to the cluster directly from the sensor then you will not have a PID for it as the ECM/PCM doesn't have the data.
 

YUKON87

Well-Known Member
Well there looks to be more to investigate there. That bit 0 of 1973 also sets high when in manual 2. So it doesn't look to be as simple as it first looked. Now if I want to go further with this bit 0 of 1973 I need to learn what unique things happen when the trans is shifted to 2nd manually!
I haven't read further down but I'm pretty sure my 03 Yukon does this when shifted into second to indicate on the cluster "traction control disabled".

I haven't read further down but I'm pretty sure my 03 Yukon does this when shifted into second to indicate on the cluster "traction control disabled".
To further this I have a TC button inside of my vehicle to di
sable traction control and enable a E- Locker giving me positrack. My rear differential also automatically locks up during a specified RPM range naturally to get me positrack. This may happen in a more complex manner as well depending on what mode you run in.

To further this I have a TC button inside of my vehicle to disable traction control and enable a E- Locker giving me positrack. My rear differential also automatically locks up during a specified RPM range naturally to get me positrack. This may happen in a more complex manner as well depending on what mode you run in. If my memory serves me well today it seems like I also remember there are subtle differences in the transmission as well, both physically and functionally, to include my 4 l60e.

The thing to do here is look at your wiring diagram for the vehicle. That will show where the oil pressure sensor is wired to. If it goes to the cluster directly from the sensor then you will not have a PID for it as the ECM/PCM doesn't have the data.
I believe his oil pressure guage will be a two wire. One running to Cluster and another running to PCM. Just like the fuel gauge in my 2005 4.2 L Envoy.

To remind everyone this both works with my Elm generic and my obdlink MX Plus. In testing a new PID, It's more efficient to run a header of "8CFEF8". This broadcast to all nodes when testing an individual PID for simplicity within torque app.

[Mod edit: Multiple successive posts merged. Please try to keep everything in one post.]
 
Last edited by a moderator:
OP
TJBaker57

TJBaker57

Well-Known Member
I believe his oil pressure guage will be a two wire. One running to Cluster and another running to PCM. Just like the fuel gauge in my 2005 4.2 L Envoy.

The 5.3, 6.0, and 4.2 oil pressure switches and sensors on the GMT360 platform all wire solely to the PCM. No wires to the cluster from these oil pressure devices.

Screenshot_20210531-175951.png
 
OP
TJBaker57

TJBaker57

Well-Known Member
Lets bring this somewhat back on topic. Or close to it at least.

Lets say for some reason you would like to display the value given by the PCM to the cluster for the oil pressure. Even if in the case of the 4.2 it is not a true value.

There is no such PID on my 2002 4.2 with P10 PCM so how do I get that data?

The cluster gets the oil pressure value by means of a message broadcast by the PCM on the serial data line. The cluster does not request this data, it seems to be updated whenever there is a change in value and the cluster is programmed to listen for this and other similar messages.

I learned some time ago, (and may have posted about it already and forgot) how to make such a request. In the case of oil pressure it is setup in Torque Pro like this...

Screenshot_20210531-181801.pngScreenshot_20210531-181815.png
 
Hey TJ,
Have you ever done any diagnosis on tac modules and dbw stuff?
I have a situation where my pedal only gives me 34% when running.
Will give me 100% key on engine off.

Pid 22131E01 gives me desired 34%
Pid 2212B101 gives me actual throttle 34%

Are these accurate?

Suggestions on other data sources?
 
OP
TJBaker57

TJBaker57

Well-Known Member
Hey TJ,
Have you ever done any diagnosis on tac modules and dbw stuff?
I have a situation where my pedal only gives me 34% when running.
Will give me 100% key on engine off.

Pid 22131E01 gives me desired 34%
Pid 2212B101 gives me actual throttle 34%

Are these accurate?

Suggestions on other data sources?
Do you mean you are giving 100% accelerator pedal but the PCM/ECM is only commanding ~34% (desided and actual)??

At first guess I would think the PCM/ECM believes there is a problem somewhere and is limiting your power. Troubles like an accelerator pedal sensor issue or the like.
 
Yes. I don't know why it would do that without throwing a code.

Reduced engine power should throw a code.
I've never heard of it allowing it to rev to redline just very slowly.

It's perfectly snappy at lower rpms, it just starts to run out of steam after 3-4k
 

Mooseman

Moderator
Is this in D or P/N? When not in a drive gear, the PCM limits the rev to ~4000.
 

Brado

New Member
I can also cycle the front axle disconnect, fuel pump, Evap vent and/or purge valves, and A/C relay.
Could likely uncover a few more as well. Other than the fan I think these are best reserved for diagnostic purposes, and the fan should likely not be keyed up at high RPM. I imagine the normal functions of the PCM prevent too much fan engagement at high RPM.
Hello,

I have searched (and read!) for several hours, but not found the EVAP vent valve command PID's. I have been through all seven pages of this fabulous thread, and I have learned a TON. I would like to tinker with a current EVAP problem we have (on a 2003 Chevy 6.0) using Torque. I would like to create a dashboard similar to the one you made in Post #156 for fan speed control, but for testing EVAP.

I envision it would be similar to the following, but would have the relevant EVAP commands added:
Torque_Evap_Dash.jpg

The above image came from here: https://www.facebook.com/GM3800Tips...5-on-some-cars-and-p0442-lar/595748833907616/

Can you please help with information/PID's for the following:

EVAP vent valve status
Command to open vent valve
Command to close vent valve
Command to change the purge valve % open
Command to *quickly* close the purge valve

I have already added the FTP PID, and can already see the fuel tank pressure with Torque.

Thanks in advance!
 
OP
TJBaker57

TJBaker57

Well-Known Member
Can you please help with information/PID's for the following:

EVAP vent valve status
Command to open vent valve
Command to close vent valve
Command to change the purge valve % open
Command to *quickly* close the purge valve


It is true that I have not posted commands for device control. And this would not be the place to do so in any event, being they are not the focal point of this thread, ie: PIDs.

As you noted, I have said that I can "cycle" such things as EVAP and others. However, the action is very temporary, taking effect for only 5 seconds before reverting to their natural operational state. In order for the commanded state to remain in force an additional "test tool present" message needs to be sent at no greater than 5 second intervals. This is what the high level scantools do. It is not so easily done with apps like Torque Pro and inexpensive obd2 adapters. I have attempted to this a few times without much success.

I will look over my notes to see if I have an EVAP Vent status pid that works on my 02 4.2 TrailBlazer and perhaps also for my 05 5.3 Yukon.
 
OP
TJBaker57

TJBaker57

Well-Known Member
EVAP vent valve status

Did not previously have this but did some quick testing at my bench setup and have confidence in the following brief summation...

Mode & Pid:22111001
Name:Evap_Vent
Header:6C10F1 (or maybe Auto)
Equation:Lookup(Bit(A:4)::1='Closed':0='Open')
 
OP
TJBaker57

TJBaker57

Well-Known Member
So I have been digging in again somewhat and thought I had identified a new PID. Well new to me at least. After the discovery I googled up what I had found only to discover that many years ago the PID was called out elsewhere though no equation was ever posted and it is not included with the Torque Pro App extended [GM] PID set. So it shall be added here.

The PID is for the torque converter clutch lockup apply solenoid. If that is correct terminology. What I have trouble with is keeping it straight in my head that the greater the duty cycle, the less the lockup pressure is applied. Not being overly well versed in automatic transmission operations doesn't help. I guess the solenoid bleeds off pressure that would otherwise go to the TCC clutch??

At any rate, when my TCC in my 2002 4.2 LL8 with factory original calibration from 2001 is fully applied and locked up (0-2 rpm slip) the Tech 2 reports a duty cycle of as low as 13% to maybe as high as 34%, varying between the two as conditions require. This at 65 mph, cruise on, flat ground. When disengaged it reads a rock steady 96%. When stopped it reads 0% which I guess is disabled.

I know there were PCM updates that addressed transmission operations so others values may vary.

The below settings for the PID imitate the Tech 2 readings...

Mode and PID:22197001

Names are as you wish of course...

Units: %

For the equation I got fancy. The idea that the lower the percentage value the greater the apply pressure until you hit zero when it is disabled troubled me so I used this:

LOOKUP(A::0='OFF':1~255=A/2.55)

This equation looks at the reported value and if it sees zero it will read "OFF" in the display. But if the value is in the range of 1 to 255 it will do the math and send that to the display. (first time I've done this, I think it's kind of neat)

At first I used a variant where I reversed the percentage to read greater at a greater apply pressure but am currently using the form that the Tech 2 uses. Here is the variant...

LOOKUP(A::0='OFF':1~255=(255-A)/2.55)

Moving on here is the header...

6C10F1 (may also work with 'Auto')



DISCLAIMER: I have only my own vehicles to try this out on so I cannot know if it will work for others. I did see this same PID# called out for other GM vehicles so that argues it may be applicable to others.
 

shaggn85

Member
TFP Switch A/B/C. (Post #17, top left gauge) A couple of days ago I had little idea of what this was. Transmission Fluid Pressure manual valve position switch. Do what now??

I googled the term and came up with a diagram and an understanding of the switch and its output and in working these data streams I managed to match the switch output to PID 1951, bits 5, 6, and 7, in the order A, B, and C. (Thank goodness for spreadsheets) For a display I match the decimal equivalent of these 3 bits and substitute text indicating the positions as we would see them such as Park/Neutral, Drive, Reverse and so on.
This switch cannot distinguish between Park or Neutral as the valve body pressures are the same in these 2 positions. (Or so I've read)
Could this be useful somehow? I have no idea, but I found it and it works to display the switch position, if not the individual channels of A, B, or C. This switch will not indicate changes in transmission selection without the presence of fluid pressure so if one shifts through the selections with the engine off no change is seen of course.

Name = Transmission Fluid Pressure Switch A/B/C
PID = 221951(append 01 for faster response in Torque)
Scale = x1
Units =Bit Mapped
Equation = Lookup(A>5::5='P/N':4='Reverse':1='Drive':3='3rd':7='2nd':6='1st')
Header = Auto

Previously I have posted a PID for Park/Neutral as 221131, bit 2. That PID/bit does indeed indicate Park/Neutral as a value of 1 and all else as 0. That PID 221131 also contains things like crank request, starter relay command and a couple of other items I have yet to even hazard a guess. I have to remind myself that we are not in fact seeing the actual switch data. The PCM is seeing that information and outputting these PIDs that we then call up. I can only make logical guesses at where the PCM is getting its information based on testing and watching the data streams. I see that P/N as displayed by PID 221131 bit 2 changes without the engine running so it is not a derivative of the TFP switch. So where does it come from?

Transmission Range Switch A/B/C/P ?? (Post #17, center left gauge) Again I say "Do what now?" More tests, more googling, more noodling around and I find this switch is also represented in PID 1951 as bits 0,1,2, and 3. It has 4 switch outputs and through combinations represent all positions including separate park and neutral indications. I believe this to be a switch on the drivers side of the transmission. Since this has separate park and neutral indications it doesn't look like a candidate for the source of the 221131 bit 2 P/N indicator. I may never know what is that source so I will move on knowing only that it does appear to indicate P/N, if not an actual switch position. To further muddy the waters there is also a previously unmentioned PID 221920 (seen in post #17, bottom left gauge) that also displays a Transmission Selection with a single bit (#1 thru 7) each representing one of 7 positions, P,R,N,D,3,2,1. Confused yet?? I can tell you I am! I am currently wondering if this PID 221920 is for use by the Instrument Cluster for the display there.

Back to that Transmission Range Switch A/B/C/P.
PID = 221951( yes, this is the same PID# used above but we will be using different bits from it. And again I say "append 01 for faster response in Torque)
Scale = x1
Units = Bit Mapped
Equation = Lookup(A-(A>5)*32::6='Park':3='Reverse':10='Neutral':9='Drive':0='3rd':5='2nd':12='1st')
Header = Auto

And just for completions sake here is what I am currently using for PID 221920. I did not alter the value of A here and there exists a possibility that this will be erroneous if ever a value appears in bit #0. I have a solution for that if it comes up.

Name = Trans Select
PID = 22192001 (I have already appended the 01)
Scale = x1
Units = Bit Mapped
Equation = LOOKUP(A: :128='Park':64='Reverse':32='Nuetral':16='Drive':8='3rd':4='2nd':2='1st')
Header = Auto

Whew!!

Hey TJ, new here but been using Torque for a while.. I am trying to find the TFP PID for my 4L80E on a 1999 6.5 Turbo Diesel. I tried the values you had above but it does not return data. Not sure what vehicle you used this on, but how did you do the data dumps to find the correct PIDs?
 

shaggn85

Member
Hey TJ, new here but been using Torque for a while.. I am trying to find the TFP PID for my 4L80E on a 1999 6.5 Turbo Diesel. I tried the values you had above but it does not return data. Not sure what vehicle you used this on, but how did you do the data dumps to find the correct PIDs?

Let me clarify my question as the more i read, the more specific i can be. I am assuming that each model/make etc... has its own set of PIDs that manufacturers use.

Your vehicle, despite being GM, does not have all the same PIDs as my GM. I am trying to understand how you find new PIDs.

Are you creating a spreadsheet with incremental PID#s, uploading to torque Pro then hunting through the list?
 

shaggn85

Member
Let me clarify my question as the more i read, the more specific i can be. I am assuming that each model/make etc... has its own set of PIDs that manufacturers use.

Your vehicle, despite being GM, does not have all the same PIDs as my GM. I am trying to understand how you find new PIDs.

Are you creating a spreadsheet with incremental PID#s, uploading to torque Pro then hunting through the list?
Well, i just answered my own question and found it.

Created an incremental list of the 19xx PIDs. Used the formula you guys came up with for the P/N, R, D4,D3 etc... and just scrolled through the list until i found the PID that did what i expected.

Voila.

If any of you have a 1999 6.5 Turbo Diesel Suburban, it look like the PID for the TFP switch position is 221904.

next i will find the Gear Selected PID.

this is awesome as i have been trying to fix a nuisance P1810 code after a trans rebuild.
 
OP
TJBaker57

TJBaker57

Well-Known Member
Let me clarify my question as the more i read, the more specific i can be. I am assuming that each model/make etc... has its own set of PIDs that manufacturers use.

Your vehicle, despite being GM, does not have all the same PIDs as my GM. I am trying to understand how you find new PIDs.

Are you creating a spreadsheet with incremental PID#s, uploading to torque Pro then hunting through the list?


As you have surmised, there are indeed different PIDs across GM vehicles. However, there are a lot of GM PIDs that are the same as well across vehicle platforms.

I began with scouring the web for resources and found some that way. I found posts and documents that explained how to request PIDs from vehicles using serial terminal apps like the old Hyperterminal of Windows. Eventually I found a good Android serial terminal app with macro and log file support. I already had a good working relationship with spreadsheets so it was a natural for me use spreadsheets to both generate the PID requests as well as process the results that were captured in the terminal apps log files.

Now even though I can easily gather up a list of PIDs that the vehicle supports that doesn't tell me what the data is or even what kind of data it is. A voltage, a switch setting, a pressure, engine related or transmission related and so on. That's when observation and recording of data streams comes along.

This is just a summation. It is a highly time consuming affair to say the least.
 
OP
TJBaker57

TJBaker57

Well-Known Member
Well, i just answered my own question and found it.

Created an incremental list of the 19xx PIDs. Used the formula you guys came up with for the P/N, R, D4,D3 etc... and just scrolled through the list until i found the PID that did what i expected.

Voila.

If any of you have a 1999 6.5 Turbo Diesel Suburban, it look like the PID for the TFP switch position is 221904.

next i will find the Gear Selected PID.

this is awesome as i have been trying to fix a nuisance P1810 code after a trans rebuild.


One key for confirming that what you are looking at is indeed the TFP switch and not some other positional switch like the range switch is this: The TFP will only change if the vehicle is running where the range position switch will change with the engine off.
 

shaggn85

Member
One key for confirming that what you are looking at is indeed the TFP switch and not some other positional switch like the range switch is this: The TFP will only change if the vehicle is running where the range position switch will change with the engine off.

correct. when the engine is off and key on, it shows 2nd gear. This makes sense since thats all switches off.

got lucky on the first one that i found it really quick and you had done the work to create the formula.

Now i want to try and break the separate signals (A/B/C) out to see where this thing is going stupid. Any suggestions there would be much appreciated and a tremendously useful diagnostic tool.
 
OP
TJBaker57

TJBaker57

Well-Known Member
Now i want to try and break the separate signals (A/B/C) out to see where this thing is going stupid. Any suggestions there would be much appreciated and a tremendously useful diagnostic tool.


I have to run out on an errand, but this is from my notes (of course, also in spreadsheet). The TrailBlazer PID has two separate data points in the one PID. TFP and also the Transmission Range Switch. It's a bitmapped PID where each bit represents fhe state of an output or input as the case may be.

Bit Mapped. TFP Switch = bits 5,6,7 = A,B,C. Transmission Range Switch = Bits 0,1,2,3 = A,B,C,P
 
OP
TJBaker57

TJBaker57

Well-Known Member
If you don't aldeady have, you will need a diagram of the switch internals like this...

Screenshot_20210629-074411.png
 

shaggn85

Member
its looking like on my vehicle, the Trans range select is not in the same byte as the TFP values.

Time to go hunting. yay!
 
OP
TJBaker57

TJBaker57

Well-Known Member
Now i need to brush back up on binary and binary operations to isolate the A/B/C etc..


Here I have substituted the binary of the three outputs A, B, C in that order in place of the english wordings. Might this work for your purpose?? (do check my work of course for accuracy)

Screenshot_20210629-103437.png
 

shaggn85

Member
I ended up doing the same kinda thing. I just output the raw number so i can tell what its doing. Still looking for the Gear range though. gotta do my day job though first ha!
 
OP
TJBaker57

TJBaker57

Well-Known Member
man, i just can't find this PID for gear range... what a pain. TJ, i admire your abilities and am jealous.

So let's clarify a little. Is it the actual current gear engaged that you are after or more simply the displayed gear selection like that seen in the cluster??

If it is the former, the actual gear in effect at the time, the PID will display an unchanging 1 unless you are actually driving and the gears are changing. Makes it harder to spot.

With a lot of trial and error I learned how to create a grid in Torque Pro and a way to change the PID set loaded into that same grid, without having to recreate the grid every time. I can load up to 40 PIDs at a time however with that many displayed the refresh rate is abysmal. However it does help in spotting things that change when stationary, like the transmission range display. I think I have posted this screenshot earlier...

Screenshot_20201125-122843.png


Other useful tricks are using a spreadsheet to generate the finished csv file for import to Torque Pro, eliminating the tedious process of entering PID data into Torque Pro manually.

Things learned over several years of doing this!!
 

shaggn85

Member
Looking for the displayed gear. Basically, i want to catch any disagreement between the gear selected on the column and the gear that the TFP switch is indicating from oil pressure.
 

shaggn85

Member
I have not found the gear range yet... but i may have solved my issue. My trans plug had an intermittent connection on the TFP C circuit.

i've cleaned up, de-pinned, retensioned, and repinned the N-P-R leads. I think this should solve my problem. What i think was happening is that after a cold-soak, the C lead was losing its connection due to wear/vibration. It would work, then i'd hit a bump, and it would drop the signal. i put a tiny crimp in the tube leads, just enough to make solid contact on the trans plug pins.

crossing fingers.
 

dirkelstein

New Member
A short time ago I posted a new pid I discovered for the Fan Speed of a 4.2 in a 2002 Trailblazer. It was properly suggested by MRRSM that I repost that information here so here I am. It is possible that this is my first original post!

I have been spending a great deal of time fiddling with these PIDs of late and have additional informations that I will post on this thread.

So as posted elsewhere the PID for Fan Speed to enter into Torque extended PIDs is 22162B (I confirmed only on a 2002 4.2). 22 being the mode or service and 162B the actual PID. Header should be set to "Auto" (cAsE sEnSiTiVe) and the equation is "A * 16". Spaces here don't matter. Units are RPM and Scale is x1.

Since that other post I have discovered that if one adds an "01" the the end of these extended PIDs the Torque app will receive the data quicker from the PCM as Torque won't need to cycle through formats seeking an answer from the PCM. I snooped the Class 2 bus while using Torque and found that with the "header" left blank many extended pids fail. When set to "Auto" (CasE sEnSiTiVe) Torque first sends the PID as entered in the extended PID definition and with many of the PIDs the PCM essentially rejects the request. Torque sends the same request again and is again rejected. Then Torque adds the "01" to the end of the PID, as in this case would be 22162B01, and bingo, the PCM answers with the data requested on the first request, speeding up the original startup at least. At first look I believe once Torque gets the answer it was seeking it remembers the format for the duration of that session but not further. You can see this using the test button in Torque while connected to your vehicle. Without the "01" appended there is a noticeable delay in the initial response time.

A short time ago I posted a new pid I discovered for the Fan Speed of a 4.2 in a 2002 Trailblazer. It was properly suggested by MRRSM that I repost that information here so here I am. It is possible that this is my first original post!

I have been spending a great deal of time fiddling with these PIDs of late and have additional informations that I will post on this thread.

So as posted elsewhere the PID for Fan Speed to enter into Torque extended PIDs is 22162B (I confirmed only on a 2002 4.2). 22 being the mode or service and 162B the actual PID. Header should be set to "Auto" (cAsE sEnSiTiVe) and the equation is "A * 16". Spaces here don't matter. Units are RPM and Scale is x1.

Since that other post I have discovered that if one adds an "01" the the end of these extended PIDs the Torque app will receive the data quicker from the PCM as Torque won't need to cycle through formats seeking an answer from the PCM. I snooped the Class 2 bus while using Torque and found that with the "header" left blank many extended pids fail. When set to "Auto" (CasE sEnSiTiVe) Torque first sends the PID as entered in the extended PID definition and with many of the PIDs the PCM essentially rejects the request. Torque sends the same request again and is again rejected. Then Torque adds the "01" to the end of the PID, as in this case would be 22162B01, and bingo, the PCM answers with the data requested on the first request, speeding up the original startup at least. At first look I believe once Torque gets the answer it was seeking it remembers the format for the duration of that session but not further. You can see this using the test button in Torque while connected to your vehicle. Without the "01" appended there is a noticeable delay in the initial response time.
Great Posts. Thanks for sharing all you learn.
I think I want / need to sniff the CAN bus while my scan tool (EFI Live) is connected and displaying certain PIDs.
How did you connect both the Torque device AND your sniffer. Perhaps an OBD2 splitter cable?
 
OP
TJBaker57

TJBaker57

Well-Known Member
Great Posts. Thanks for sharing all you learn.
I think I want / need to sniff the CAN bus while my scan tool (EFI Live) is connected and displaying certain PIDs.
How did you connect both the Torque device AND your sniffer. Perhaps an OBD2 splitter cable?


If you are speaking of an actual CAN bus vehicle, ISO 15765-4, and NOT a vehicle using the GM Class 2 serial data bus, SAE J1850 VPW, then I'm afraid I cannot say. My experience is limited to only the older GM Class 2 SAE J1850 VPW arena. I don't know doodley-squat when it comes to CANBUS, ISO 15765-4.

On the other hand, I know many times the term CANBUS is used loosely to refer to ANY vehicle network regardless of actual bus types.

Splitter cables, YES!! Readily available online though quality control can be lacking. I once bought an OBD2 pigtail for benchtop top tests and the wire colors did not match the provided diagram. I also have 5 OBD2 adapters to facilitate multiple device/app operations.

A good serial terminal app is practically imperative to get anywhere with such activities. I use the free "Serial Bluetooth Terminal" by Kai Morich. Vastly better than fiddling with Torque Pro (or others) for discovering PIDs and other such things. Support for logfiles and macros makes an enormous difference.

And then there is the "language" of the serial data bus to learn so you know what you're looking at!! It can be daunting. Maybe that's why there is scarce participation in this and related discussions!!
 

YUKON87

Well-Known Member
When testing a PID, could you turn header printing on than run a broadcast header when testing a PID to see which module respononds? If I can remember correctly I tried this many months ago with success.
 

Online statistics

Members online
2
Guests online
89
Total visitors
91

Members online

Forum statistics

Threads
21,557
Messages
613,924
Members
15,618
Latest member
iceref63

Secure Browsing

Top Bottom