Installed BT module; DIC NO COMM, engine dies
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
Installed BT module; DIC NO COMM, engine dies
I pulled the stock radio in my 2003 M6 convertible, installed a BT module, and reassembled. To power the BT module I ran the included wire to the included mini-tap (add-a-fuse) circuit which plugs in to the fuse 11 spot in the interior fuse box, and includes a slot for the old fuse.
The car starts, immediately dies, throws "Reduced Engine Power", "Service Engine Soon", and "Low Fuel". HVAC powers on but the radio does not. Coolant temp gauge is maxed, oil pressure and fuel gauges are at zero. Battery charge appears accurate. Prior to pulling the radio, everything was functioning properly.
I'm posting this in the (vain) hope I just popped a fuse, because if it's more than that it will be time to have it towed to the local Corvette specialist. I guess I'll be purchasing some electrical test equipment soon...
The car starts, immediately dies, throws "Reduced Engine Power", "Service Engine Soon", and "Low Fuel". HVAC powers on but the radio does not. Coolant temp gauge is maxed, oil pressure and fuel gauges are at zero. Battery charge appears accurate. Prior to pulling the radio, everything was functioning properly.
I'm posting this in the (vain) hope I just popped a fuse, because if it's more than that it will be time to have it towed to the local Corvette specialist. I guess I'll be purchasing some electrical test equipment soon...
Tech Contributor
Joined: Jan 2007
Posts: 19,493
Likes: 1,178
From: Dyer, IN
I pulled the stock radio in my 2003 M6 convertible, installed a BT module, and reassembled. To power the BT module I ran the included wire to the included mini-tap (add-a-fuse) circuit which plugs in to the fuse 11 spot in the interior fuse box, and includes a slot for the old fuse.
The car starts, immediately dies, throws "Reduced Engine Power", "Service Engine Soon", and "Low Fuel". HVAC powers on but the radio does not. Coolant temp gauge is maxed, oil pressure and fuel gauges are at zero. Battery charge appears accurate. Prior to pulling the radio, everything was functioning properly.
I'm posting this in the (vain) hope I just popped a fuse, because if it's more than that it will be time to have it towed to the local Corvette specialist. I guess I'll be purchasing some electrical test equipment soon...
The car starts, immediately dies, throws "Reduced Engine Power", "Service Engine Soon", and "Low Fuel". HVAC powers on but the radio does not. Coolant temp gauge is maxed, oil pressure and fuel gauges are at zero. Battery charge appears accurate. Prior to pulling the radio, everything was functioning properly.
I'm posting this in the (vain) hope I just popped a fuse, because if it's more than that it will be time to have it towed to the local Corvette specialist. I guess I'll be purchasing some electrical test equipment soon...
Instructor
Joined: Sep 2022
Posts: 123
Likes: 66
From: Sylvania, OH
If you unplug the BT module at the fusebox, will the car then act normal? If it is still a problem, trace your wiring and look for a pinched wire. Actually, trace your wiring either way. If it starts running normal you probably still have a wiring problem. I did the same thing with a BT module and everything worked fine so you're not doing something funny.
Melting Slicks
Joined: Sep 2008
Posts: 3,139
Likes: 802
From: Espanola New Mexico
You have managed to mess up the serial data buss, it is a single wire that connects all of the cars electronic modules. If you look for codes thru the DIC I am pretty sure you will have no comms on all the modules.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
With what you described sounds like a serial data bus issue…I’d unplug that radio and then see what happens…I can do what you’re seeing by just applying a power or ground to the data bus…what other wires do you have connected to your BT and to where ??
Last edited by C5 Diag; May 3, 2024 at 07:56 AM.
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
The BT module sits between the passenger side 20-pin plug on the back of the radio and the socket; essentially mates between them with its own socket and plug. The only other BT module connection is a wire to draw power from the accessory line at fuse 11, joining the "add a fuse" mini-tap that is in now in that fuse location.
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
If you unplug the BT module at the fusebox, will the car then act normal? If it is still a problem, trace your wiring and look for a pinched wire. Actually, trace your wiring either way. If it starts running normal you probably still have a wiring problem. I did the same thing with a BT module and everything worked fine so you're not doing something funny.
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Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
When you say "plug that radio" do you mean remove the BT module from the radio connection (just uninstall the BT module)? A serial bus issue sounds accurate based on yours and @mmartinez descriptions, as the DIC is getting NO COMM on all the modules. Given that, it does sound like the car will need help from someone with more ability (and test equipment) than I possess.
Drifting
Joined: Mar 2018
Posts: 1,365
Likes: 414
From: New Jersey
When you say "plug that radio" do you mean remove the BT module from the radio connection (just uninstall the BT module)? A serial bus issue sounds accurate based on yours and @mmartinez descriptions, as the DIC is getting NO COMM on all the modules. Given that, it does sound like the car will need help from someone with more ability (and test equipment) than I possess.
Tech Contributor
Joined: Jan 2007
Posts: 19,493
Likes: 1,178
From: Dyer, IN
When you say "plug that radio" do you mean remove the BT module from the radio connection (just uninstall the BT module)? A serial bus issue sounds accurate based on yours and @mmartinez descriptions, as the DIC is getting NO COMM on all the modules. Given that, it does sound like the car will need help from someone with more ability (and test equipment) than I possess.
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
As usual, taking everything apart the second time took a fraction of the time that the first attempt did. That center trim piece surrounding the HVAC controls and the radio is a right nasty beast, though.
Thread Starter
Instructor
Joined: Aug 2021
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From: Highland Village, TX
Sorry; should have responded to you earlier; that fuse was fine. I think in the first install I just messed up the placement of the wiring. Thank you for the input, though, it was certainly worth the small effort to check. I really need to get a new digital multimeter.
Tech Contributor
Joined: Jan 2007
Posts: 19,493
Likes: 1,178
From: Dyer, IN
Sorry; should have responded to you earlier; that fuse was fine. I think in the first install I just messed up the placement of the wiring. Thank you for the input, though, it was certainly worth the small effort to check. I really need to get a new digital multimeter.
Thread Starter
Instructor
Joined: Aug 2021
Posts: 183
Likes: 111
From: Highland Village, TX
I wonder that as well; how did moving wiring around "fix" a serial bus issue? Or rather, how did the first wire routing create the issue? Certainly freaked me out enough that I thought I'd fried something.
Drifting
Joined: Mar 2018
Posts: 1,365
Likes: 414
From: New Jersey
Last edited by C5MSG2004Vert; May 3, 2024 at 08:23 PM.