Chasing an Electrical Gremlin
Thread Starter
Racer
Joined: Apr 2007
Posts: 408
Likes: 2
From: Naperville, IL
St. Jude Donor '13, '15
Chasing an Electrical Gremlin
I am having an electrical issue with my 01 vert. When I turn the radio on the car seems to “reset” itself: the gauges sweep, the corvette message shows up and the hVAC starts up. It does not happen all the time; I also can not duplicate the issue on a consistent basis but it is definitely related to the powering up of the radio because I can get the car to repeat the issue just not consistently.
Car also does not seem to be throwing any codes when this happens.
Also the car would not start recently, there was no power to the car(i.e. no interior lights, no hood lamp, key inserted and nothing happens), went into to check the forum for answers and came back to the car and it started immediately…
Have checked and cleaned all grounds that did not seem to be the issue. I also checked the ignition switch and that seems to be operating properly. Thanks to the great writeups by Bill Curlee
Had the battery (10months old) checked, it was tested as good.
So now I am driving around without the radio on and don’t have the above issue, any thoughts on what I should check next or recheck will be greatly appreciated.
Car also does not seem to be throwing any codes when this happens.
Also the car would not start recently, there was no power to the car(i.e. no interior lights, no hood lamp, key inserted and nothing happens), went into to check the forum for answers and came back to the car and it started immediately…
Have checked and cleaned all grounds that did not seem to be the issue. I also checked the ignition switch and that seems to be operating properly. Thanks to the great writeups by Bill Curlee
Had the battery (10months old) checked, it was tested as good.
So now I am driving around without the radio on and don’t have the above issue, any thoughts on what I should check next or recheck will be greatly appreciated.
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
Electrical Problem
Hi, I'm gonna give a few off the cuff suggestions, you may have already checked. Often when unexplained things happen like that it is the fault of a battery going bad, I know you said you checked it, did you have it load tested by someone that knows how. Otherwise loose or corroded cables , both of them at the battery and, starter, and fuse block could cause intermittent strange symptoms. The other thought is an intermittent short in the radio that draws down the electrical system momentarily and causes havoc.
Maybe some of the other guys will have some suggestions. But it's best to verify 100% that you have a good battery, and clean tight connections before looking anywhere else.
Good Luck
Maybe some of the other guys will have some suggestions. But it's best to verify 100% that you have a good battery, and clean tight connections before looking anywhere else.
Good Luck
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
PM to Bill Curlee as he may have some more thoughts on it. My first guess is that your radio is somehow shorting out the data-buss. It does connect to it.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
No way to test it that I'm aware of. If you have someone there nearby, best thing I can suggest is to borrow someone's radio and try it in yours as long as its the same. I would think your car would be storing a code in the DIC that would reflect something, but you said its not...Bill Curlee is the best person for this stuff. He might suggest looking inside the door-jam accordian tubes for a wire there that possibly shorts to the frame, but somehow I doubt that this is happening with yours. Then again, the speakers go through those.... are all of the speakers working?
Thread Starter
Racer
Joined: Apr 2007
Posts: 408
Likes: 2
From: Naperville, IL
St. Jude Donor '13, '15
okay so it happen on the way home from work today, did not have the radio on , check for codes and have a U1000 code. Will look that up and start checking the grounds and cables again
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
Code Help
Sounds like a bad connection, plug, or ground. Check the cables as well as the grounds. Might even be a loose plug at one of the accesories or behind the dash. My best guess would be a loose cable either at the battery or starter, especially with the car not starting that time. The starter cable has been known to loosen up, if they are good and the battery is confirmed good then possibly the grounds.
Good Luck
++++++++++++++++++++++++++++++++++
All GM Vehicles Using Class 2 Communications Diagnostic Strategy for DTC U1000 or U1255 - kw BCM code EBTCM radio RIM #PIT3154 - (Sep 10, 2004)
All GM Vehicles Using Class 2 Communications Diagnostic Strategy For DTC U1000 or U1255
.
The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.
Condition/Concern:
DTC U1000 or U1255 set current or history, with or without other DTCs
Recommendation/Instructions:
DTC U1000 Class 2 Data Link
DTC U1255 Lost Communications
These DTCs set when the control module does not receive a message that it was expecting from another control module, and does not know which control module did not send that message.
If the DTC U1000 or U1255 is set in history with other DTCs set current or history, diagnose the other DTCs first.
If the DTC U1000 or U1255 set current, this usually indicates a module that is currently not communicating or a configuration issue. For example, if the control module is configured for an option (ie: Onstar, Keyless Entry, Memory Mirrors, etc.) that the vehicle does not have, it may expect to receive a message regarding this missing feature. This would usually occur due to the control module being recently replaced and incorrectly setup.
When the DTC U1000 or U1255 is current, the module that is not communicating may not even be listed on the Tech 2 on the Diagnostic Circuit Check/Class 2 Message Monitor list.
If the DTC U1000 or U1255 has set in history without other DTCs, replacing the control module setting the DTC is most likely NOT the solution. The module that has set the code is looking for an input from another module that is not communicating. Since the module did not receive an input that it is expecting to see, it sets a U1000 or U1255 which indicates there was a loss of communications. Look at the customer’s complaint (ie: intermittent, erratic tachometer operation); this will probably be a better indication of the control module that is the source of the concern.
.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.
Models:
(All GM vehicles using Class 2 communications)
.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
Last edited by bestvettever; Jul 3, 2008 at 07:11 PM.
Thread Starter
Racer
Joined: Apr 2007
Posts: 408
Likes: 2
From: Naperville, IL
St. Jude Donor '13, '15
Thanks For The Help
After reading the posts and double checking my grounds and starter wires. I went to the battery cables, and notice the two cables leading to the fuse box where loose so I tighten the nut.
I test drove the car while cycling the radio on and off, the problem did not return
As this was always an intermittent issue I am not ready to declare victory just yet.....
Thanks guys for help
I test drove the car while cycling the radio on and off, the problem did not return
As this was always an intermittent issue I am not ready to declare victory just yet.....Thanks guys for help
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
Electric Problems
After reading the posts and double checking my grounds and starter wires. I went to the battery cables, and notice the two cables leading to the fuse box where loose so I tighten the nut.
I test drove the car while cycling the radio on and off, the problem did not return As this was always an intermittent issue I am not ready to declare victory just yet.....
Thanks guys for help
I test drove the car while cycling the radio on and off, the problem did not return
As this was always an intermittent issue I am not ready to declare victory just yet.....Thanks guys for help
Good Luck
