PDA

View Full Version : ODBII not reading


BGarrett
02-02-2013, 04:30 AM
I have a 2004 Freightliner passenger van, and I've found that any type of ODBII-based scanner won't connect to it. A Sprinter-specific scanner, however, reads the codes just fine. I've tried two different scangauges and several different code readers with no luck. Finally, I got an Autel Maxidiag Elite, and it works fine in Sprinter mode, but won't even connect in ODBII mode. I thought this was normal until I saw some posts from other 04 owners getting data from their scangauges. Could this be because the passenger vans are assembled in Germany rather than the US, and therefore have a different computer, or do I likely have a problem with mine?

bc339
02-02-2013, 05:34 AM
Well....my scangauge works just fine in ours. I've had the SGII for a few years with no issues. I followed the setup procedures and have not had any problem reading the generic OBDII codes.
How old is your scangauge and have you had any updates to the firmware that they offer?

Bruce

geoffs
02-02-2013, 07:08 AM
No problems with the Scangauge II in my van either.
SG is about 2 years old and hasn't had any firmware updates.

BGarrett
02-02-2013, 11:27 AM
Thanks for the info.
I tried 2 brand new scangauge II units, but neither would connect. Tech support at scangauge also said it should work, but they did give me my money back when we couldn't resolve the problem. I guess that there must be something different or wrong with my van. I have been told that a 2004 "might not be fully ODBII compliant", but I would think that it should at least connect. By the way, what year is your Sprinter, and do you have a cargo or passenger version?

johnshmit
02-02-2013, 12:50 PM
Check connector pins:
http://www.auterraweb.com/obdiipinout.html

Sprinter tool has external power, but generic tools are powered by connector itself.
Different tools can use different protocols from different pins.
Not fully OBDII compliant means its only guaranteed to support government mandated set of pids.

johnshmit
02-02-2013, 01:10 PM
50054
You should see ~2.5 v on CAN pins with regular DVOM

Aqua Puttana
02-02-2013, 01:19 PM
Some time ago there was a thread/post from someone who was having trouble with interfacing with a DAD or other scan tool. If my memory is correct they eventually had some issue which required reflash or some other higher level ECM communication. That wouldn't work either. The communication problems were traced to an aftermarket radio, er... head unit which had been installed. Somehow someone had connected into the CAN bus wiring when that was installed. Surprisingly (at least to me) that tagged on wiring didn't affect normal operation of the systems to the point of failure, but it did interfere with module communications through the OBDII port.

Do you have an aftermarket head unit, GPS, or other gadget which may be connected to the CAN bus? It might be worth exploring. I don't think that they specified the wiring that had been tapped into. My suspicion would be that with the head unit it was the Speed Signal wire which is used on the OEM units for volume control input. That wire should not be used except for the OEM radioes.

Sorry I can't offer more. Please take the time to get back to us if you resolve your problem. I'd hate to see this thread left hanging. vic

johnshmit
02-02-2013, 02:06 PM
OBD II connector has Dianostic CAN-B in it. If faulty, it will not affect Powertrain CAN-C network.
CAN-B is fault tolerant and radio will operate on one wire, OBD II will not.

Aqua Puttana
02-02-2013, 02:15 PM
OBD II connector has Dianostic CAN-B in it. If faulty, it will not affect Powertrain CAN-C network.
CAN-B is fault tolerant and radio will operate on one wire, OBD II will not.
OK. I think I understand what you are saying, but I'm having trouble relating it to what I posted.

Are you saying that the Radio CAN-B wire tagged on could affect the OBDII communication or not?

To be clear, what I posted is for information only and is not a diagnosis. Thanks. vic

johnshmit
02-02-2013, 02:19 PM
Yes, radio connected to CAN-B can disrupt OBD II communication and not affect powertrain.
So it does confirm your info.

autostaretx
02-02-2013, 03:17 PM
johnsmit posted the "generic" OBD socket pinnage... the USA/NAFTA T1N Sprinter socket uses most of the other pins for Sprinter-specific diagnostic lines.
When using a "real" Sprinter diagnostic system, it may not ask anything of an "OBD" nature, but restrict all of its communications to the other lines.
Sprinter:

50061

--dick

Aqua Puttana
02-02-2013, 03:24 PM
Dick,
That's good information to include for this thread.

There might even be some more applicable information to be gleaned from this thread. FWIW. vic

http://sprinter-source.com/forum/showthread.php?t=23288&highlight=ECM+ECU

bc339
02-02-2013, 07:03 PM
Here's the pinout information and the protocols.
This website (pinoutsguide.com) also has other vehicle pinouts, but here's the MB guide:
http://pinoutsguide.com/CarElectronics/mercedes_obd2_diag_pinout.shtml

I'm looking into building an Arduino based OBD interface project to replace the DAD microcontroller - any arduiniees out there?

Bruce

BGarrett
02-05-2013, 01:39 AM
Thanks to everyone for all the great info on this subject, but I'm afraid that I left off one very important piece of info from my last post:
After I returned the scanguage II, I bought an Autel Maxidiag elite off of ebay. It works perfectly, but only if you first select Sprinter from the list of manufacturers, and connect in Sprinter mode. (I'm pretty sure that the Sprinter mode uses CAN, but I'll verify that When i get home) The Autel is a port-powered device, so it seems that my power pins must be OK, but it won't connect in ODBII mode either. I haven't had a chance to compare which pins in the plug are populated to the port diagrams, or check voltages, but I will update this thread when I do.

So...there must either be something wrong that prevents the ODBII from working, or I have a really unusual vehicle. I guess it's somewhat academic now, since I can read the Sprinter codes with the Autel, but it bothers me that I can't read ODBII codes, and I can't help wondering if it's related to the driveability problem that I've been unable to resolve with this van since I bought it. (The van cuts out momentarily any time it's at mid-throttle and it's warmed up)

BTW, IMHO the Autel Maxidiag is very nice Sprinter code reader at a good price. (About $350). It's derived from the software of the $3,000 professional MaxiDas DS708 that my Sprinter mechanic uses.