NO COMM error on all codes???
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
NO COMM error on all codes???
I have a 2001 C5 Convertible that we purchased new. I had the module in the passenger side floor area replaced months ago. Been working fine. A couple of weeks ago I started having some issues that looked electrical in nature. Now when I check my DIC computer error codes I get NO COMM on all computers. The engine will start but says reduce power. The power windows and radio will not work at all. I did get some water in through the convertible top weeks ago and had to dry out the carpet. Does this sound like some ground or short issue? Parked in my garage right now. I was going to take it (towed) to a great local guy but he is busy for the next month. Any ideas on where to start?
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
No ideas?
I have a 2001 C5 Convertible that we purchased new. I had the module in the passenger side floor area replaced months ago. Been working fine. A couple of weeks ago I started having some issues that looked electrical in nature. Now when I check my DIC computer error codes I get NO COMM on all computers. The engine will start but says reduce power. The power windows and radio will not work at all. I did get some water in through the convertible top weeks ago and had to dry out the carpet. Does this sound like some ground or short issue? Parked in my garage right now. I was going to take it (towed) to a great local guy but he is busy for the next month. Any ideas on where to start?
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
I just had a similar issue and solved it. In my case the ground connection on the engine block was loose and engine would shut off/ not start unless I shook the wires (until I tightened the bolt of course 
)
Your problem sounds similar to this though: https://www.corvetteforum.com/c5-tec...vers-door.html
Let us know how it turns out!
) Your problem sounds similar to this though: https://www.corvetteforum.com/c5-tec...vers-door.html
Let us know how it turns out!
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
Didn't work
I just had a similar issue and solved it. In my case the ground connection on the engine block was loose and engine would shut off/ not start unless I shook the wires (until I tightened the bolt of course )
Your problem sounds similar to this though: https://www.corvetteforum.com/c5-tec...vers-door.html
Let us know how it turns out!
) Your problem sounds similar to this though: https://www.corvetteforum.com/c5-tec...vers-door.html
Let us know how it turns out!
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
The engine block ground is on the passenger side, just under the header and just above the starter, it is a 15mm bolt. Check out this as well for the other ground locations:
https://www.corvetteforum.com/c5-tec...tion-long.html
https://www.corvetteforum.com/c5-tec...tion-long.html
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
On another note, have your battery tested, and if all is well move on from there. Could also be your BCM is damp or moist, I read somewhere that it does not like ANY water at all. Just food for thought hopefully it guides you in the right direction
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
Thanks. The battery is less than one year old but just for the heck of it I put my large battery charger on it overnight. I will also look at the BCM but I had that replaced with a remanufactured one about 6 months ago or so. Been working great until now.
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
Ground not loose
Checked the ground up near the battery towards front and not loose. Opened connnector and looked OK with no corrosion. Checked BCM in passenger floor and looks OK on the outside. Still NO COMM on all DIC codes. Any other suggestions?
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Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Hmm, Have you checked your fuses (both internal and external panel)? did you check the ground on the engine block that I was talking about? All starter nuts are tight? Have you opened the accordion on both sides of your door, pulled out the wires, opened the connection to see if there are any problems/bad connections? Checked power seat connections for problems? Other than that, maybe Bill Curlee will chime in. He has some pretty good write ups that helped me diagnose some of my problems.
Thread Starter
Intermediate
Joined: May 2012
Posts: 49
Likes: 0
From: Florida
Hmm, Have you checked your fuses (both internal and external panel)? did you check the ground on the engine block that I was talking about? All starter nuts are tight? Have you opened the accordion on both sides of your door, pulled out the wires, opened the connection to see if there are any problems/bad connections? Checked power seat connections for problems? Other than that, maybe Bill Curlee will chime in. He has some pretty good write ups that helped me diagnose some of my problems.
Racer
Joined: Apr 2009
Posts: 488
Likes: 2
From: Myrtle Beach SC
Additional suggestions:
1) Open up the passenger footwell, remove the shorting bars from the star connectors, and clean everything up.
2) While you're in there, check to see if there are any loose connections to the BCM.
3) Check the power supply fuse for the diagnostic port (IPEC fuse #29).
4) With a test light, probe the power and ground pins on the datalink connector itself...check for continuity.
5) Check resistance of the ground pin/connection with a DMM. You are looking for less than or equal to 2 ohms, I believe.
Hope this helps. Post back your results.
1) Open up the passenger footwell, remove the shorting bars from the star connectors, and clean everything up.
2) While you're in there, check to see if there are any loose connections to the BCM.
3) Check the power supply fuse for the diagnostic port (IPEC fuse #29).
4) With a test light, probe the power and ground pins on the datalink connector itself...check for continuity.
5) Check resistance of the ground pin/connection with a DMM. You are looking for less than or equal to 2 ohms, I believe.
Hope this helps. Post back your results.
Last edited by sunchaser73; Oct 30, 2013 at 08:39 AM.