Service Theft deterrent/class 2 communication error Has ANYONE found a solution?
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Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, Service Theft deterrent/class 2 communication error Has ANYONE found a solution? in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; Part one: The Rant Much like many people on this forum, my service theft deterrent system light came on and ...
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    Service Theft deterrent/class 2 communication error Has ANYONE found a solution?


    Part one: The Rant


    Much like many people on this forum, my service theft deterrent system light came on and has not gone off. I won't belabor the details as this problem has been posted several times by several people. The car runs and the key is not stuck. My car is currently sitting in a dealers service bay, where it has been for two weeks ( with no end in sight). The service tech replaced the ECM to no avail. In short the tech can't find anything wrong. yet the problem still persists. On top of this, I was told by the service manger at the dealership (very politely) that because my car is OLD, fixing it is not a priority for them. though he promised it would be fixed....eventually. there's only one tech with the skills to solve the problem, and he's needed elsewhere. Now if I can tell the tech what's wrong and how to fix it, they'll be happy to do the work. Hmm....ok Fine. I suggested consulting with a GM tech, ask the guys that designed and built the car right? WRONG. sorry sir your car is just TOO OLD to b a concern. There's an easy solution, car breaks down, buy a new one, but I digress.

    Part two: The Appeal


    So finally I get to my plan, I want to collect as many viabale suggestions as I can. I know that the tech has gone through the standard service procedures. Since it's been demonstrated so far to be ineffective. I need some "out of the box" thinking. Whatever is wrong is either ridiculously small, or something the engineers didn't anticipate breaking down as these cars age (remember guys, you may be next). I'm also appealing to any Cadillac/GM techs or reps that are part of this forum 'cause I know you're out there (Hi Laura). My car may not be a priority to Cadillac, but it's a priority to ME. And I know that paying the bill WILL be a priority when the time comes

    Part Three: The Clues

    Through the Nav system (retrofitted my me) I'm able to access the OBD II. from this I know that the ECM and EBC aren't giving out any data and that the theft deterrent module was completely out of communication. that's been replaced so I know it's not the module. the tech has confirmed this by checking each module individually. So , what is the point of commonality between the ECM, EBC (electronic break control), and VTD (Vehicle theft deterrent). Of course the temp and gas gauges don't work. And, as I discovered, the voice command doesn't work, not an important feature, but a possible clue. Otherwise the car runs fine. the only moda I've done are the previously mentioned Nav system and the instrument cluster, I swapped the '03 cluster for an '04.

    Conclusion:The Plan


    It's my intention to foward all the viable suggestion I get to the Service Manager ant Service Tech inhopes that someone will come up with something the tech hasn'r thought of. I figure that the tech has become frustrated and is now going in circles. Hopefully I can give him some new directions to pursue. If anyone has had any kind of luck with this let me know what worked for you (other than the ECM, that's been tried) I will publish the solution when/if I get one.

    Thanks to all in advance

    Wendel

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    propninja's Avatar
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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solutio

    UPDATE:
    After a week of sitting idle, my car has once again become a priority for the dealer to fix (in other words they have nothing else to do). I did some research via various forums and online articles and passed on some recommendations on to the Service Manager who tells me that his tech had come to similar conclusions. I'll wait until I see how things pan out before I publish my findings.

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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solutio

    just encouraging you on this. I wish most posters were as methodical. What I do know as you already probably know is as opposed to relays as in older card the CTS has modules for every thing, windows, heater you name every system has a dedicated module which reports back to the ECM via a serial data communication. This actually makes diagnosis a little easier. with two point of connection it's either point a, point b or the wide in between. please continue to post yoru findings i'm curious on this one as I don't think the forum has got a grasp on the serial communication of the different systems to the ecm yet. We are still in the plug this or that in and see if it works, as opposed to using scopes etc to check the continuity of connections.

    Quote Originally Posted by propninja View Post
    UPDATE:
    After a week of sitting idle, my car has once again become a priority for the dealer to fix (in other words they have nothing else to do). I did some research via various forums and online articles and passed on some recommendations on to the Service Manager who tells me that his tech had come to similar conclusions. I'll wait until I see how things pan out before I publish my findings.

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    Cadillac mat is offline Cadillac Owners Member
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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    Have you called Cadillac customer service directly?

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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    Interesting you ask that. Cadillac Customer service contacted ME. They're members on this forum and will occasionally reach to individuals apparently if you complain about dealers. Since they're not techs( and my car is OLD) there wasn't much they could do. That's not to say that there wasn't something going on in the background I'm not aware of. On a related note, i did inquire of the Service Manager as to the possibility of consulting with a GM engineer in the problem. "Sorry your car is too OLD it's not a priority" Are you getting the feeling I'm a bit peeved about that comment? I wonder what the reaction would be when the time comes to pay the bill any my reply is: Sorry my car is too OLD it's not a priority for me to pay you.

    I will say this now, this is NOT a Cadillac problem (theft deterrent et al) it's a GM problem and is common to all of their cars though to a lesser degree.

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    Cadillac mat is offline Cadillac Owners Member
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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    I would think maybe customer service could at least do something about the "it's not a priority.". But cool they reached out to you.

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    Cadillac mat is offline Cadillac Owners Member
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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    Resolution ?

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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    Resolution:

    Three weeks and $2300 later, my car is fixed. Now I can report The problems that have been reported about cars dying and keys stuck in the ignition in NOT the ecm (though it is intimately involved) it's the BCM (Body Control Module) or more correctly BCS (Body Control System). If my research is correct,there are 8 modules: each of the four doors, the Rear Integration Module (RIM), the Dash integration Module DIM, Voltage Control Module (VCM) and the Vehicle Theft Deterrent (VTD). The Reader's Digest version of the problem goes something like this: The ECM and the BCS share information back and forth, the ECM handling the engine management functions and the BCS handling things like lighting, HVAC windows etc. Theft deterrent is the major overlap point Exapmle: the ECM send information about the fuel level and temperature to the BCS which sends that info to the instrument cluster. Now, if something happens to any of the modules in the BCS, the system begins sending out corrupt data. When that happens IT STOPS TALKING TO THE ECM AND VTD. It is at this point that the VTD assumes the car is stolen and shuts everything down. GM in it's infinite wisdom however, programs a fail safe. If the VTD can't communicate with the BCS it bypasses the start code and allows the car to start. The ECM then responds the only way it knows how how: it turns on the check engine light the Theftt deterrent light, the ABS light and anything else that may be impacted. The problem with all this is, a code scanner can't communicate directly with the BCS. It has to go through the ECM. So to find the problem a tech has to use old school methods of finding the problem, disconnect each module one at a time to see what changes. and if that doesn't work, then they have to probe each wire on at a time to see of there is a loss of signal, then trace that back to the source. This process took THREE WEEKS for my car. Note this doesn't include the week my car sat idle in a repair bay.

    What to look for

    The problem turned out to be water damage in the rear cabin. I had a short to ground in some of the communication wiring and corrosion in a couple of the splice packs. Finding and fixing this required removing the seats, carpeting and the center console. That being said, look for signs of water leaking into your car. This could be anything from a puddle to rust stains. finding wiring problems is three parts science and one part dark magic, which is why it' such a bear to find and fix. This doesn't the ECM isn't involved (mine had water damage as well and had to be replaced) but the ECM is not the final arbiter or source of the problem. For what it's worth. this is not a Cadillac Only problem, it's across the entire GM line, though to a lesser degree. Cadillacs just have more modules to foul up. Or in the words of Mr Scott " The more you tinker the pluming, the easier it is to clog up the pipes"

    Summary


    The engine is primarily effect by sensors and can be easily diagnosed via a scan tool. the ECM does not control body functions. Anything that can be classified as a body function (or malfunction) look to the BCM or BCS t ifind the problem. Keel in mind, I'm not a mechanic or a tech so do not consider this to be expert advise. Do your research. For a problem like this one you're going to need a fracking good electrician. if anyone else has better intel feel free to chime in!, As I said this a simplified explanation of events.
    briggy likes this.

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    Re: Service Theft deterrent/class 2 communication error Has ANYONE found a solution?

    Quote Originally Posted by propninja View Post
    I will say this now, this is NOT a Cadillac problem (theft deterrent et al) it's a GM problem and is common to all of their cars though to a lesser degree.

    This is true. My 2008 impala ltz has had issues with the theft deterrent system. The computer on my impala likes to randomly say my keys aren't programmed to use the car. Have had to get my keys reprogrammed 3 times since we bought the car in 2010. Great car but talk about a bipolar electrical system.

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