Anti-Theft System Troubleshooting

Can anyone tell me if the service documentation available to a Freightliner Sprinter technician provides troubleshooting guidance for the factory installed anti-theft system? My new Sprinter is back at the dealer today to determine why the anti-theft alarm goes off at random times. The first call from the service tech did not instill confidence when he started off the conversation, "well it's not showing any codes, so... " Prior to taking my Sprinter in for service, I did verify that the alarm would go off at an inconvenient time after I manually deactivated the interior motion sensors. Thanks for any information that will enable me to conduct an informed discussion with the service tech.

Brian

If Carl doesn't say something, I'll post some service manual content.... I don't recall "extensive t-shooting guidence" on any topic in the service manual, including the factory anti-theft system. I'll also see if there's any info in the printed training material.... but I gotta get home first.

I do vaguely recall someone posting about their alarm going off w/o provocation. You probably searched already though.... and there probably isn't an answer.

-Jon

PS: I found it, and I don't see an answer.... just my own, discouraging posting at the bottom of the thread...... gotta go

https://sprinter-source.com/forums/showthread.php?p=22018

Did you disconnect the motion sensors in an attempt to prevent the false alarms or are they a result of such actions ?

Yes, I purposely deactivated the motion sensors before locking the van, and the alarm still went off. That happened twice prior to the service appointment. If I had more time, I'd try deactivating the tow-away sensor. And just for grins, I should measure the starting battery voltage after I shut off the alarm. Hopefully, the dealer will figure it out.

Brian

Jon,
While the material you posted doesn't go into troubleshooting detail, it does provide a good system overview. I didn't know that the siren module is fairly independent of the roof control module, and the siren module can sound the siren if it detects a power supply or communication circuit fault. My dealer's Sprinter tech is scheduled to work the issue tomorrow morning. Thanks for posting the service manual info.

Brian

i have had similar problems with my alarm system. i have found that i cannot leave the radio on with the alarm set. i wonder if there is shock sensor on board as well.

bb

I didn't have time to read - or even skim this material - but I hope it helps.

-Jon

Hood A-jar sensor maybe ?

The Sprinter-Source forum server must have thrown a DTC this afternoon. Looking back at this thread, it appears I read Jon's service manual file and replied to his message 97 minutes before he actually posted it. I guess anything is possible in the NCV3 universe.

I'll add hood-a-jar and heated-rear-door-glass sensors to the topic list for tomorrow's discussion with the service tech.

Brian

Hi Brian,

From the service manual info, which I only just skimmed (again, apparently, because I quoted this in the other thread)....


As far as I can tell, this is sort of a dead end, in terms of documented diagnostics. I can't find a Vehicle Theft Security System menu item on the scan tool, and I tend to believe the first sentence. I'd hoped Carl would chime in before your service appt tomorrow, but at least you'll know that they may not be lying to you about what they can know....

I have no idea where to go from here....

-Jon

jdcaples said:

Hi Brian,

From the service manual info, which I only just skimmed (again, apparently, because I quoted this in the other thread)....

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the VTA system or the electronic controls or communication between other modules and devices that provide some features of the VTA system. The most reliable, efficient, and accurate means to diagnose the VTA system or the electronic controls and communication related to VTA system operation requires the use of a diagnostic scan tool. See the Vehicle Theft Security System menu item on the scan tool. Refer to the appropriate diagnostic information.​

As far as I can tell, this is sort of a dead end, in terms of documented diagnostics. I can't find a Vehicle Theft Security System menu item on the scan tool, and I tend to believe the first sentence. I'd hoped Carl would chime in before your service appt tomorrow, but at least you'll know that they may not be lying to you about what they can know....

I have no idea where to go from here....

-Jon

Click to expand...

Well I finally saw the thread. Intermitant alarm issues are never covered in the service manual. . There is a bright side . Now we all know how it works (thanks Jon ). I haven't had to diagnose alarm issues YET, but I have dealt with other vehicle alarm issues.
The best way to determine the problem is by using the scan tool to see what was the last reason for activation, (usually stated in sensor displays) I cannot and will not give anyone a rock solid answer to what the problem may be, but door lock switches and ajar switches (hood also) have mostly been issues with "Gost cycles" . I am sorry that I do not have a answer, but I will be watching the thread to see how everything panned out. please keep us all informed, and good luck.

Carl

On the 17th of Sept, Brian wrote...

CocoaVan said:

Jon,
...
My dealer's Sprinter tech is scheduled to work the issue tomorrow morning.
...

Brian

Click to expand...

It's now the 21st and I lack the will power to hold off posting any more....

What happened?

-Jon

Allrightythen...

So I'm walking back to van with Buster just now, 50 yards away, the alarm goes off.

There is nobody around, nor loud or low frequency sounds.

I open the door and as I get in I notice a big fat fly buzzing around. Could it be possible?

The window was open a bit...

Hope this is the last of it...

OrioN said:

Allrightythen...

So I'm walking back to van with Buster just now, 50 yards away, the alarm goes off.

There is nobody around, nor loud or low frequency sounds.

I open the door and as I get in I notice a big fat fly buzzing around. Could it be possible?

The window was open a bit...

Hope this is the last of it...

Click to expand...

I can tell you from personal experience that an insect can set off the alarm, and it does not have to be overweight. It does have to be bigger than a smallish, Seattle mosquito. There is no funding available to support a quantitative study (in the lifestyle to which I'm accustomed).

So far, it's been a No-Trouble-Found situation. What bothers me is that I can disable the motion sensor, and the alarm still goes off. That tells me that one of the other sensors is acting up. Those sensors are: doors, hood-ajar, heated rear door glass, and inclination. Also, the siren module can set itself off if it detects a communications or battery problem while the alarm is set, but the siren module is supposed to store a DTC when it does so, and the dealer is telling me no DTC's are present.

I'm planning to pick up the van today, but despite daily calls, I've not been been able to talk to the tech who's done the troubleshooting. Others have read his service notes, but they can't answer my questions. For example, I know that the tech has set off the alarm manually, but the notes don't indicate whether that action causes DTCs to be stored by the Roof Control Module (RCM) or another ECU. What I really want to know is if the dealer's scan tool can determine what sensor triggered the "last alarm," and how long that code is stored. For example, did the fact that my service appointment was several days and a few trips after the last alarm trigger generate enough activity to clear the stored code? That might be the case, because the tech could not find any evidence that the alarm was triggered. If this continues to be a recurring problem, then I want to know what is the appropriate troubleshooting procedure, and I don't want my post-alarm actions to wipe-out any diagnostic evidence.

Brian

jdcaples said:

I can tell you from personal experience that an insect can set off the alarm, and it does not have to be overweight. It does have to be bigger than a smallish, Seattle mosquito. There is no funding available to support a quantitative study (in the lifestyle to which I'm accustomed).

Click to expand...

Jon,
The next time you have StarMobile hooked up to your Sprinter, please poke around the RCM ECU and see what vehicle alarm related data is stored. I have some tests planned when I bring the Sprinter home. I'm going to attach small objects of varying size to a fine thread fixed, and swing them in pendulum fashion at various points in the van to see what triggers the alarm. I'll probably use washers as the target object, held in place with an electromagnet. Once I have an object that repeatedly triggers the alarm, I'm going to test whether the feature that deactivates the intrusion sensors actually works.

I appreciate everyones' ideas and comments.

Brian

CocoaVan said:

The Sprinter-Source forum server must have thrown a DTC this afternoon. Looking back at this thread, it appears I read Jon's service manual file and replied to his message 97 minutes before he actually posted it. I guess anything is possible in the NCV3 universe.

I'll add hood-a-jar and heated-rear-door-glass sensors to the topic list for tomorrow's discussion with the service tech.

Brian

Click to expand...

Time of postings is when the forum is out of sequance with the server it's not uncommon, but very annoying. Like you posted but it does not show unless you look back on the older postings and there it is
Richard

Walking the RCM-ECU attached.

I don't have access to my Sprinter right now. The best I can do is run the simulator and walk to menus.

-Jon

PS: The RCM ECU Data screen has some historic info.

Carl,

StarMOBILE Application Desktop Client 10.01.23 was released, but I can't find the release notes.
The current version of WiTECH is still 10.01.22, last I checked.

Is there any utility in "dot 23" that might help Brian?

If you have a clean installation, you need a scan tool to turn on vehicle simulations in StarMOBILE Desktop Client (or more time than I have to figure out if that's in some INF or other text file in the dcc tools tree). I'd have to do a clean install of SDC and I'd need my scan tool to turn on simulations in it.
I'm no where near my computer, scan tool or Sprinter right now.


-Jon

I hope your on Holiday John