Setting up Car Scanner ELM OBD2

[Sqrly]

I can't insert images from my pc into "conversations" so I have to insert them here.

I just installed the app from the google store and upgraded to pro yesterday.

TJbaker57 is helping me setup it up for my vehicle.

Details: I'm using the Car Scanner ELM OBD2 on my Moto G6 (Android 9) and the Veepeak Mini Bluetooth OBD II Scanner for Android Only.

On my 2004 GMC 4WD Envoy XUV SLE 2.4 I6 Manufactured Dec 2003

Note: I've also installed the app on my Nvidia Shield K1 Tablet (Android 7)

Hello again,

I have the Car Scanner ELM OBD2 app installed and upgraded to pro. The BT adapter should arrive tomorrow.

Q: Should I just go through the default setup and get back to you after it's all working or do you have reccomendations on ways to do things differently during the setup?

My vehicle specs are my signature.

The general setup is good.


For your 2004 XUV, in "Connection Profile" select Chevrolet, then I select "OBD-II / EOBD".

There is another option that may work which I haven't explored and that is "OBD-II + SAE J1850 (Duramax VPW").


Essentially, our old GMT360 uses the GM implemtation of the SAE J1850 VPW communication standard. There is no CAN (ISO 15765-4) communications on our older GM vehicles.

These settings will load a collection of data point definitions. Not all will work with your specific vehicle.

The app developers keep adding more as they become aware of them, and some of these data points will list different variations for the same data. Some will work on cars, some on trucks, some for specific models and so on.


After we get up and running I can supply more data point definitions in the form of a file to be imported into the app as "Custom Sensors".

I can't put pics in here, I put them in a post Setting up Car Scanner ELM OBD2

I'm glad I asked. I was going to use GMC 2004-present profile (1st pic)

Your saying use the first Chevrolet option (2nd pic) but that has a different SAE/ISO number then what you said my vehicle uses.

The third option you mention, (3rd pic) does have the matching SAE J1850 number.

FYI My vehicle manufacture date is Dec 2003.

 

[TJBaker57]

What can be confusing is the use of overlapping standards and such. Each standard might address a different layer or what have you.

What I use is the option "OBD-II / EOBD".

I don't know if the next option which adds "CAN" will work or not, but the "CAN" protocol is not present in your 2004 XUV.


I think I have had a look at the last option that includes "Duramax" in the name but I don't think it adds anything useful for our platform.

 

[Sqrly]

What can be confusing is the use of overlapping standards and such. Each standard might address a different layer or what have you.

What I use is the option "OBD-II / EOBD".

I don't know if the next option which adds "CAN" will work or not, but the "CAN" protocol is not present in your 2004 XUV.


I think I have had a look at the last option that includes "Duramax" in the name but I don't think it adds anything useful for our platform.

In that case I will test the different profiles on my specific device and vehicle and report back what results I get.

 

[Sqrly]

I got my new tools and I hooked them up. I tried the first profile (2004 - present+can) and it threw an error telling me to use a different profile. I chose the 3rd profile (Duramax VPW) and it seems to be happy. I haven't tried any others yet as I don't have much time to tinker with it atm.

I tapped "Emissions Tests" and it says everything passed. I tapped "DTC" and there's a ton of codes.

Does this mean the profile isn't working right? They all say "Status: Pending fault present, Test has not been completed" at the end. Or are these just old stuff that never got cleared out? Or perhaps it's literally that I need to complete these tests somehow?

Oh, I love that the app can export to my color notes app

OK, I had a little more time, I tried the 2nd profile "GMC OBD-II / EOBD" and got the exact same codes. I did check the "hide archived codes" box.

To avoid confusion, I'm updating the report below to the one using the "GMC OBD-II / EOBD" profile. Everything was identical except the profile and time.

Car Scanner ELM OBD2
Version: 1.112.3/201123/GP
DTC report
Connection profile: GMC OBD-II / EOBD Date: 10/25/2024 12:44:29 PM
============================
OBD-II
No DTC found.
============================
ECU ID: 10
No DTC found.
============================
ECU Address $58
No DTC found.
============================
ECU Address $40
No DTC found.
============================
ECU Address $1AECU Address $1A
DTCs: 18
----------------------------
U1255 [0xD255]
Serial Data Line Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
U1000 [0xD000]
Class 2 Communication Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0300 [0x4300]
Rear propshaft signal circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0305 [0x4305]
Front propshaft speed sensor/system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0306 [0x4306]
Motor A/B circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0321 [0x4321]
Transfer case lock circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0327 [0x4327]
Encoder circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0359 [0x4359]
4LO discrete output circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0374 [0x4374]
General system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0379 [0x4379]
Front axle system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0550 [0x4550]
Electronic Control Unit Malfunction; Electronic Control Unit ROM Malfunction; Electronic Control Unit Internal Malfunction; Electronic Control Unit EEPROM Incorrect Programming
Status: Pending fault present, Test has not been completed
----------------------------
B0770 [0x8770]
AWD/4WD indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0775 [0x8775]
4HI indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0780 [0x8780]
4LO indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0785 [0x8785]
2HI indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0790 [0x8790]
Transfer case Neutral indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B2725 [0xA725]
ATC Mode Switch Circuit Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
U1301 [0xD301]
Class 2 Short to Battery
Status: Pending fault present, Test has not been completed
============================
ECU Address $6A
No DTC found.

 

[TJBaker57]

I got my new tools and I hooked them up. I tried the first profile (2004 - present+can) and it threw an error telling me to use a different profile. I chose the 3rd profile (Duramax VPW) and it seems to be happy. I haven't tried any others yet as I don't have much time to tinker with it atm.

I tapped "Emissions Tests" and it says everything passed. I tapped "DTC" and there's a ton of codes.

Does this mean the profile isn't working right? They all say "Status: Pending fault present, Test has not been completed" at the end. Or are these just old stuff that never got cleared out? Or perhaps it's literally that I need to complete these tests somehow?

Oh, I love that the app can export to my color notes app

OK, I had a little more time, I tried the 2nd profile "OBD-II / EOBD" (But GMC not Chevy) and got the exact same codes. I did check the "hide archived codes" box.

Car Scanner ELM OBD2
Version: 1.112.3/201123/GP
DTC report
Connection profile: GMC OBD-II + SAE J1850 (Duramax VPW)Date: 10/25/2024 12:04:11 PM
============================
OBD-II
No DTC found.
============================
ECU ID: 10
No DTC found.
============================
ECU Address $58
No DTC found.
============================
ECU Address $40
No DTC found.
============================
ECU Address $1AECU Address $1A
DTCs: 18
----------------------------
U1255 [0xD255]
Serial Data Line Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
U1000 [0xD000]
Class 2 Communication Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0300 [0x4300]
Rear propshaft signal circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0305 [0x4305]
Front propshaft speed sensor/system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0306 [0x4306]
Motor A/B circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0321 [0x4321]
Transfer case lock circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0327 [0x4327]
Encoder circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0359 [0x4359]
4LO discrete output circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0374 [0x4374]
General system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0379 [0x4379]
Front axle system malfunction
Status: Pending fault present, Test has not been completed
----------------------------
C0550 [0x4550]
Electronic Control Unit Malfunction; Electronic Control Unit ROM Malfunction; Electronic Control Unit Internal Malfunction; Electronic Control Unit EEPROM Incorrect Programming
Status: Pending fault present, Test has not been completed
----------------------------
B0770 [0x8770]
AWD/4WD indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0775 [0x8775]
4HI indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0780 [0x8780]
4LO indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0785 [0x8785]
2HI indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B0790 [0x8790]
Transfer case Neutral indicator circuit malfunction
Status: Pending fault present, Test has not been completed
----------------------------
B2725 [0xA725]
ATC Mode Switch Circuit Malfunction
Status: Pending fault present, Test has not been completed
----------------------------
U1301 [0xD301]
Class 2 Short to Battery
Status: Pending fault present, Test has not been completed
============================
ECU Address $6A
No DTC found.

I would reselect the connection profile and try the one I suggested a few times "OBD-II / EOBD". See if anything changes.



So all of those codes are for the 4WD system. The Transfer Case Control Module (TCCM) is the ecu at address $1A.

I can't say I have ever seen so many faults from a TCCM that is installed in a vehicle! I do see this many when bench testing one as then none of the inputs are connected sometimes.

If the codes remain on the recommended connection profile I think I would start by resetting the TCCM by removing the ATC fuse under the hood for a minute or so then reinserting the fuse. It also may be worth having a peek at the TCCM itself to verify the harness connectors are firmly attached.

 

[Sqrly]

So all of those codes are for the 4WD system. The Transfer Case Control Module (TCCM) is the ecu at address $1A.

I can't say I have ever seen so many faults from a TCCM that is installed in a vehicle! I do see this many when bench testing one as then none of the inputs are connected sometimes.

Could those codes be caused by someone who didn't know what they were doing moving the 4WD rotary knob to different positions while the vehicle was moving during the initial test drive and having it fail to shift the TC to protect itself from stupid requests?

 

[TJBaker57]

Could those codes be caused by someone who didn't know what they were doing moving the 4WD rotary knob to different positions while the vehicle was moving during the initial test drive and having it fail to shift the TC to protect itself from stupid requests?

No. The systems programming should prevent any shifts it deems invalid. In fact, the owners manual states you can shift to any 4WD mode "at any speed". I would caution against doing so at high speed though.

Personally I feel OK shifting into or out of 4WD modes up to say 45 mph or so.

Now then, any shift into or out of 4Lo should only be done while in neutral and not moving more than say 1 mph. A little slow rolling helps the gearing line up for a soft clunk.

 

[TJBaker57]

Does this mean the profile isn't working right? They all say "Status: Pending fault present, Test has not been completed"

I'm a little slow sometimes.

When I first read this I remember it striking me as odd, something I hadn't seen before.

Just now at dinner it hit me.


The TCCM doesn't have "pending" codes. The codes there are either CURRENT, or HISTORY.

Either this is a result of the connection profile in use, or a bug in the Car Scanner software.

And now that I think about it, it has a familiar tone to it. I may have stumbled on this previously and meant to take it up with the developer and forgot all about it.

 

[Sqrly]

If I hit the "clear" button, it pops up another "are you sure" screen and that one says that some codes can not be erased from the history. I haven't tried to clear them by hitting the confirm button or tried to reset the TCCM by pulling the fuse, yet.

This weekend I'll try to clear them first, if they persist I'll pull the fuse. Afterwards I'll actually shift the TC through the different modes and see if the lights turn solid then look for codes again. I did shift it to A4WD and 4-Hi once. I've never actually put it in 4-Lo.

No. The systems programming should prevent any shifts it deems invalid. In fact, the owners manual states you can shift to any 4WD mode "at any speed". I would caution against doing so at high speed though.

Personally I feel OK shifting into or out of 4WD modes up to say 45 mph or so.

Now then, any shift into or out of 4Lo should only be done while in neutral and not moving more than say 1 mph. A little slow rolling helps the gearing line up for a soft clunk.

It does indeed prevent shifts it deems invalid, such as turning the rotary knob to 4-Lo while moving well over 2 mph. I know because I tried it to see if it would block it.

The little 4-Lo LED light just flashed for a bit like it is supposed to and then the 4-Hi lit back up. Exactly what it was supposed to do according to the manual.

That why I asked if doing that would create the codes I'm seeing.

Note: I did read the manual, I'm curious how they expected people to keep the vehicle moving 2 mph in neutral?

And now that I think about it, it has a familiar tone to it. I may have stumbled on this previously and meant to take it up with the developer and forgot all about it.

I will definitely post back here my actions and results.

 

[TJBaker57]

This weekend I'll try to clear them first, if they persist I'll pull the fuse.

If you need to pass any emissions tests in your area I would avoid clearing TCCM codes with most any scantool. Many scanners send instructions to clear all codes from all modules. This resets the emissions monitors and then you cannot pass those tests until everything gets back to the ready state. Sometimes this can take quite a while.

There are ways to clear codes from ONLY the TCCM, leaving the emissions monitors alone.

Note: I did read the manual, I'm curious how they expected people to keep the vehicle moving 2 mph in neutral?

I typically do such shifts on a gentle incline and let it roll just slightly as the shift takes place. I have even pushed on flat ground with left leg out the open door !! It doesn't take much movement to let the gears align, a gentle rocking can do it.

 

[TJBaker57]

Now this is going to demonstrate some of the possibilities here.

I just used Car Scanner to read codes and I see as you have seen a lot of these results comment about codes pending and tests not yet complete.

So I wanted to see what is really going on behind the scenes here.

I used a "terminal" feature of Car Scanner to allow me to do the interactions with the OBD2 adapter and the vehicle first hand.

That is to say "I" myself will do the 'talking' to the adapter and the vehicle here.

Having already connected to the "vehicle" (which is a few modules in a drawer here in the house):

(1) I open the "Settings" menu item.

(2) I then scroll down to the "Terminal" selection.

(3) One by one I send what is seen in red below.

(4) I read/decode the results which report 4 active codes. C0321, C0359, C0379, and B2725.

All 4 of these codes have the following status bits set: Current, MIL Requested, and History. No "Pending" status bit(s) set.



At this point, still at the Car Scanner "Terminal" window if I send the value "14" (no quotes) that would clear all diagnostic data and codes in the TCCM.

Of course if the codes were active as they are in my case they of course would immediately reset back to being active "Current" codes.

That is the case here as this TCCM does not have all the inputs connected from other components of the 4WD system.

 

[Sqrly]

How are you translating the hexdecimal output to trouble codes?

Do you know where I can find the FULL ELM327DS.pdf document?

SEO has ruined the web and I just get a ton of trash results when searching the term.

 

[azswiss]

ELM327DS.pdf attached below.

 

[Sqrly]

ELM327DS.pdf attached below.

Thank you.

 

[Sqrly]

Now this is going to demonstrate some of the possibilities here.

I just used Car Scanner to read codes and I see as you have seen a lot of these results comment about codes pending and tests not yet complete.

So I wanted to see what is really going on behind the scenes here.

I used a "terminal" feature of Car Scanner to allow me to do the interactions with the OBD2 adapter and the vehicle first hand.

That is to say "I" myself will do the 'talking' to the adapter and the vehicle here.

Having already connected to the "vehicle" (which is a few modules in a drawer here in the house):

(1) I open the "Settings" menu item.

(2) I then scroll down to the "Terminal" selection.

(3) One by one I send what is seen in red below.

(4) I read/decode the results which report 4 active codes. C0321, C0359, C0379, and B2725.

All 4 of these codes have the following status bits set: Current, MIL Requested, and History. No "Pending" status bit(s) set.

View attachment 114783

At this point, still at the Car Scanner "Terminal" window if I send the value "14" (no quotes) that would clear all diagnostic data and codes in the TCCM.

Of course if the codes were active as they are in my case they of course would immediately reset back to being active "Current" codes.

That is the case here as this TCCM does not have all the inputs connected from other components of the 4WD system.

Following your instructions I cleared the TCCM codes using the terminal. Then I went back and checked for DTC and there where none.

Then I drove the vehicle and ran it through all the 4WD modes. I can visually and audibly confirm that it shifted properly into all modes. I checked the DTC again and there are still none so it's all good.

I just remembered that the previous owner did say the transmission had been rebuilt. I'm guessing that's where all the codes came from and they just never cleared them out.

This will get your attention ....

When I tap "Live Data" using the OBD-II / EOBD profile I get 35 sensors, if I use the OBD-II + SAE J1850 (Duramax VPW) profile, I get 118 sensors.

The first thing I want to do is log data on the Tourque Converter to see if it's locking up properly.

The "Calculated Instant Fuel Milage' is of interest too, if it's accurate enough.

 

[TJBaker57]

When I tap "Live Data" using the OBD-II / EOBD profile I get 35 sensors, if I use the OBD-II + SAE J1850 (Duramax VPW) profile, I get 118 sensors.

I will take a look at that. I will specifically check to see if they have incorporated some of the PIDs (Parameter ID's) I discovered and posted here on GMTNation as well as using them in the app.

Depending on what I find I will see about putting together a file for import to Car Scanner that will add the bulk of what I have worked out these past several years most of which is specific to the 4.2 LL8 engine.

Examples would be the exhaust cam VVT commanded and actual angles and variance. I also think I have the duty cycle for that one. Cooling Fan actual and desired speed. The two 5 volt sensor reference power sources. And so on.

There are a slew of transmission related PIDs available also. For my own 2002 4.2 I know I can read a few data points for the torque converter clutch. Essentially I try to duplicate what the old dealership scantool, the Tech II does.

My 2002 4L60E has no input speed sensor so I have always wondered how reliable the PID readout for TCC slip is under such conditions. I see no actual way for them to differentiate TCC slip from some other clutch pack slippage in the transmission.

So I recently made a PID definition for use in Torque Pro that takes the engine RPM, then reads the current gear from the transmission, does the calculation for the proper gear ratio, then compares that with the output shaft rpm. Still playing with that one.

Last year I requested a new capability from Car Scanner and helped the developer some so that he could implement it. Specifically I wanted to be able to request parameter data not by node-to-node service $22 messages but rather using Class B Data Communications as specified in SAE J2178. Torque Pro could do it, why not Car Scanner? They added it but I was getting some random data spikes and I haven't revisited that lately.

 

[TJBaker57]

@Sqrly

So I investigated the different connection profiles and had a look behind the scenes at the related sensors (PIDs).

I see as you do that the profile that contains (Duramax) has a lot more PIDs. Some of those will likely work for the XUV but a lot will not.

I saw a couple that resemble PIDs I have posted here on GMTNation however as users we do not have the ability to see what equations are being used for PIDs (sensors) that are included with the app.

Having seen what is there I will proceed with assembling a file for import which I will post up here in a day or so.

 

[Sqrly]

There is just so much stuff here.

On page 34 of the ELM327DS document I see that I can manually select a protocol with the terminal.

I see SAE J1850 PWM and SAE J1850 VPW.

Then I found this so I must go look closer at that OBD2 connector tomorrow.

PWM	The connector must have pins 2, 4, 5, 10, and 16
VPW	The connector must have pins 2, 4, 5, and 16, but not 10.

Having seen what is there I will proceed with assembling a file for import which I will post up here in a day or so.

So you can look in profile B and find the things that will work on vehicle A and import those PID's into Profile A? That's pretty impressive.

Until we started this converstion my experience with OBD was limited to one of those cheap code readers from the auto parts store. There is just so much here to learn.

 

[TJBaker57]

On page 34 of the ELM327DS document I see that I can manually select a protocol with the terminal.

You can set a protocol for the adapter yes. But if you want to communicate with your vehicle you must use the protocol the vehicle uses of course. Your 2004 4.2 XUV uses protocol 2, SAE J1850 VPW.

Your DLC will have:

pin 2, the J1850 single wire

pins 4 & 5, both grounds but to different points on the body

pin 16, battery positive (through fuse #13)

So you can look in profile B and find the things that will work on vehicle A and import those PID's into Profile A? That's pretty impressive.

Well sort of. A given "connection profile" will contain certain sensor definitions. These can be seen in the "sensors" menu item in "settings".

In "settings/sensors" one can add more sensors if one knows the definitions required. These will be categorized as "custom" sensors.

I can observe the sensors available in a given connection profile/vehicle profile, learn enough of the definition particulars and how they operate. Then I can recreate the sensors as "custom" sensors in a different vehicle profile.

Optionally I can construct a file that contains a selection of sensor definitions. Said file can be imported into other vehicle profiles.

It's late and I fear I am doing a poor job of explaining this.

 

[Sqrly]

How exactly does detect a misfire?

Using the Duramax profile I tapped "all sensors". I figured it was the easiest way to see what would work for my vehicle.

I can see Cyl's 2 and 3 are misfiring a lot. I know there's a threshold that must be crossed to create a trouble code and although that's not happening since I ran some injector cleaner through, I'm still seeing a lot, more so at idle. (I've only looked at it under no load, I haven't logged it while driving yet)

 

[TJBaker57]

How exactly does detect a misfire?

The PCM detects misfires by monitoring the rotational speed of the crankshaft.

I don't see any on my 2002 4.2 TrailBlazer but I see an occasional one or two on my 2005 5.3 Yukon.

 

[Sqrly]

 

[TJBaker57]

Low level 'flutter' is pretty much normal I believe.

 

[Sqrly]

The VVT is definitely working . The timing jumps 20° the moment I hit the gas.

Note: Now that @TJBaker57 shared a file with me to add those sensors to the Car Scanner app!

 

[TJBaker57]

Interesting. My 2002 has never requested or exceeded about 12.5°.

Same PID definition, just a different year.

I wonder if they changed the way the angle is reported by the later PCMs. As I understand it the maximum is 25° crankshaft angle. I have always figured my 2002 is reporting camshaft angle.

 

[Sqrly]

Interesting. My 2002 has never requested or exceeded about 12.5°.

Same PID definition, just a different year.

I wonder if they changed the way the angle is reported by the later PCMs. As I understand it the maximum is 25° crankshaft angle. I have always figured my 2002 is reporting camshaft angle.

All 4 graphs don't fit on my screen for whatever reason, here's a different screenshot showing the 4th one.

 

[TJBaker57]

ELM327DS.pdf attached below.

I was saddened just recently to learn that ELM Electronics closed up shop a couple of years ago.

Their website currently has a single page for downloading of their datasheets with a warning that this too will shut down.