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So I just bought a cheaper c5 from a member on this forum knowing it had some issues. As I am trying to work through all the trouble codes I end up with a bunch of No comm codes that lead me to believe that some of them might be connected and before I start diving into each one separately I thought I would get everyone's opinion on the best course of action.
Codes:
TCS No Comm
RTD No Comm
Radio No Comm
HVAC No Comm
A6-SCM No Comm
BCM:
B0502 H C
B0507 H C
B2482 H C
B2527 H C
It also had 3 H codes that I cleared to see if they come back but did not write them down thinking they are History: (let me know if you need these and I can take the car out this weekend and see if they come back)
LDCM
RDCM
BO-RFA
Car is a 97 Manual Trans base coupe, Manual HVAC control, no f45, bose stereo, no HUD . The car does have an aftermarket radio head unit and only the two rear speakers work. HVAC seams to work fine, could use a charge. The drivers seat controls works fine but it does slide forward and back while driving. The traction control light stays on no matter what I do. It tells me to service soon at every start up.
1) From what I can understand is that other than the TCS No Comm everything else is controlled or "regulated" by the BCM. Could I just have an issue with the BCM vs an issue with each one of these modules?
2) TCS No Comm: I know I need to address this separately, I have already cleaned all the connectors at the wheels and are starting to go down the list of ground points and clean those. I really need to get under the car and make sure its personal ground is good and that it is receiving power. Any other ideas on potential fixes?
I guess I am just looking for someone to help me through the process of eliminating theses problems, I am not new to turning a wrench but diagnosing complete electronic control systems is a first for me.
For the first 3 BCM DTC’s see if fuse #2 in the under hood fuse box is blown or missing...for the last DTC see if your horn works...if not maybe the horn relay may be bad !!...you can start there !!!...as far as the no comms sometimes these aftermarket radios or radar detectors if wires incorrectly can cause all types of issues !!...I doubt you have that many modules that are bad !!
For the first 3 BCM DTC’s see if fuse #2 in the under hood fuse box is blown or missing...for the last DTC see if your horn works...if not maybe the horn relay may be bad !!...you can start there !!!...as far as the no comms sometimes these aftermarket radios or radar detectors if wires incorrectly can cause all types of issues !!...I doubt you have that many modules that are bad !!
All fuses are present and visually good. Horn works just fine.
Sir, there are quite a few electrical “experts” on this Forum but unfortunately this is no “magic bullet” when it comes to electrical diagnostics...you have to have some electrical knowledge and some equipment...we don’t know your skill level so we can only do what we can do in front of a computer !!...when it comes to module no comms the first thing is to check their power and grounds !!
Sir, there are quite a few electrical “experts” on this Forum but unfortunately this is no “magic bullet” when it comes to electrical diagnostics...you have to have some electrical knowledge and some equipment...we don’t know your skill level so we can only do what we can do in front of a computer !!...when it comes to module no comms the first thing is to check their power and grounds !!
Understood. Thanks. I don't have any crazy equipment, just your standard ohm/volt meter and a test light. All modules appear to have power/ground to them and just not communicating with their respective contol module (if this makes any sense, I am still learning exactly how the modules are all connected). I will continue my search. Thanks again!
All of the module communicate between one another on the serial data network (class 2) which is a single wire that leaves each module and terminated at 2 splice packs (pictured) which are located to the left of the BCM...you can pop off the “comb” as we call it and see if there is any corrosion on the blades. Pin 2 of the DLC (where you hook up your scan tool to) is the serial data line and when you hook up your scan tool there you scan tool is just another module !!!...saying the modules “appear” to have power and ground isn’t good enough...you have to test...I looked to see if all of the modules that you can’t communicate with share a common ground and it appears they don’t !!...I’ll see if I can find something later...sometimes a bad ignition switch can cause some strange problems like this !!
05-01-2020, 03:43 PM
Bunch of No Comm, Need Help!
