Okay, first off, I apologize for revisiting this subject for what seems to be the 300th time! However, I have not been able to find an answer for my question within this forum, or other searches and was hoping some others may help.

I have an '02 SS, and have previously experienced the "Service Traction System" message and the "ABS" amber light. However, upon shutting off and restarting the vehicle, the problem disappeared. Last week however, the message and light came on and stayed on. Upon first instinct, I assumed I had a bad wheel speed sensor. I unplugged each sensor harness at the wheel, cleaned the connection, added some dielectric grease, and plugged them all back in. No dice, message and light are still bugging me. I called a few techs around my area and they said that you would need to have it plugged in to properly diagnose it. I own an ElmScan 5 and was unable to pull any codes. I did a little research, and came across some info regarding the Delphi DBC-7 ABS module that is on my vehicle. It states:
"
If a fault is detected, a code will be stored in the EBCM's memory, the ABS warning lamp will be illuminated and the ABS system will be deactivated for the remainder of the drive cycle. The red brake warning light may also come on if there is a possibility that the ABS malfunction may affect dynamic rear proportioning. If the malfunction is no longer present the next time the vehicle is driven, the code will become a history code and the warning lamp will not come back on. Codes will be automatically cleared from memory if no codes are set off during 100 consecutive drive cycles. There are NO flash codes available with this system so a scan tool such as a GM Tech 1, Vetronix MasterTech or similar scan tool with ABS software is required to read and clear stored codes. The DBC-7 system also provides "enhanced" data which can be read through the scan tool, including:
•Brake switch status;
•TCS switch status;
•ABS activity status;
•ETC/TCS activity status;
•Vehicle speed; and
•Number of drive cycles since a code was set."
I suppose this is why I got no codes. Well, because I needed to know which hub sensor was giving me problems, I opted to spend the weekend in remedying my other problem. The previous owner of this car, armed with what I suspect was a razor blade, managed to scratch off nearly 75% of my rear window defog grid. I set about masking off my rear window and repairing it with Permatex's Quick Grid. After I had made my repairs, I checked the voltage accross the grid, and after finding my success, I was apparently too excited to remember to turn my key back off.

Yesterday morning, I went out to find my car dead. As in nothing, my power-pack jumped didn't even get it to 8V. I let it trickle charge, got it started and was happy to see that the traction message and ABS lights were off. I got in and headed off to fill up, and tried the ABS on the sheet of ice on our street. No ABS. I accelerate to the point I know the tires will break loose. No traction message. I hit the "Trac Off" button, no action. After getting gas, I headed back to the garage, and removed each wheel speed sensor, checked them for resistance (the fronts were 1024 ohms, the rears were 1058 and 988) AC Voltage (I was able to get 300 mV out of each sensor) and as far as I know (which isn't alot) they are all within spec. I put them back on, drove the car this morning, and still have to no ABS or trac, but also no messages or lights.

[font="arial"][size="2"]So, here's my question. Can I get any codes at the d

 

So I talked to a couple more techs today regarding the problem I described in the above post. To update, I pulled off the negative battery cable last night, and bolted it back on again this morning. Still no lights. After talking to the techs, they mentioned that a number of drive cycles might be necessary; he defined drive cycles as a trip >5mi at >40 mph. Additionally, they said that though they didn't have a true number for resistance for the sensors, they usually just checked them from side to side, and if there was a large (>300 ohm) difference, they considered the one with the lower resistance bad. Regarding drive cycles, I haven't done more than 3 driv cycles of this definition, and still no ABS, but I'll try to keep you updated.

Again, any help on where to go from here would be greatly appreciated. Thanks!

-Adrian

 

Sorry, the only thing I can think of would be to hook it up to one of those big scanners at the dealership and just have them diagnose it.

 

Check and see if the hub assembly isn't bad, the speed sensor is built in to the assembly, the sensor goes bad, leading for the ABS/Traction Control to activate and always stay on in the info center in the car.[/align]

 

When I pulled off the hubs, the bearing assemblies themselves were good and tight. The techs that I spoke with told me that most likely when a bearing gets sloppy, the exciter ring and the pickup itself aren't aligned properly anymore, causing the problem with the sensor. They said that it is usually wire breakage or bearing failure that necessitates replacement of the hub. I don't think I have either, but I still don't have any lights on to help the techs with the big scanners to get any messages. I'll keep trying and thanks for the responses.

-Adrian

 

My wifes Montana had the Traction Control and ABS lights come on during a long drive in November. The dealer checked everything out and it turned out to be just low brake fluid. I was skeptical (but pleased it was so inexpensive to fix). As of right now it has been fine since they added the fluid, and with the winter we have been having both the ABS and traction control have been getting a workout. Maybe its the same with your MC.

John

 

I did glance at the fluid, but maybe I'll take a little closer look this evening. Thanks.

-Adrian

 

Well, I got it back from the dealer, and found that the ground wires in the harness that connect to the EBCM were giving an over-limit resistance. The guy stripped the harness, replaced the wires, and we are good to go. I asked him why he thought it might of happened, and he suspected general corrosion, but didn't have a definite answer. Short of having my own pinout kit and TechII, I don't feel that I could have fixed it on my own, so I don't feel too bad about paying $200 for it. Thought you might appreciate an update, thanks for the help.

-Adrian

 

Thanks for the update. We can keep that in mind when other users ask.

I'm glad that you went the dealer route... that would have been alot of wasted time just trying to guess at this one.

 

Do you happen to know if the problem wasin the harnessby the transmission?

My dealer tried to tell me that there was a TSB about it.