2004 Chevy Lumina CODE1040

Tiny
NICOL_I_NICOL
  • MEMBER
  • 2004 CHEVROLET LUMINA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
How fix the problem for code U1040
Bestregards,
nicol
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Saturday, August 22nd, 2009 AT 5:20 AM

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Tiny
MERLIN2021
  • EXPERT
Chevey doesnt show a 2004 Lumiina, and U 1040 is DTC U1001-U1254 Circuit Description Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring (Node Alive messages). A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module's "Node Alive" message. Each module on the class 2 serial data circuit which is powered and performing functions that require detection of a communications malfunction is required to send a "Node Alive" message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a DTC U1xxx , where xxx is equal to the 3 digit identification number, is set. The Control Module ID Number list provides a method for determining which module is not communicating. A module with an internal class 2 serial data circuit malfunction or which loses power during the current ignition cycle would have a Lost Communication DTC set by other modules. The modules that can communicate will set a DTC indicating the module that cannot communicate. When no message is detected from a learned identification number for five seconds, a DTC U1xxx, where xxx is equal to the 3 digit identification number, is set.


http://www.2carpros.com/forum/automotive_pictures/62217_choices_2.jpg


Battery voltage problem, maybe a loose connector. Or bad module, a TechII GM scantool may be needed to figure it out.
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Saturday, August 22nd, 2009 AT 5:37 AM
Tiny
BMRFIXIT
  • EXPERT
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring-Node Alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module's Node Alive message. Each module on the class 2 serial data circuit which is powered and performing functions that require detection of a communications malfunction is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a DTC U1xxx, where xxx is equal to the 3-digit identification number, is set.
The Control Module ID Number list provides a method for determining which module is not communicating. A module with an internal class 2 serial data circuit malfunction or which loses power during the current ignition cycle would have a Lost Communication DTC set by other modules. The modules that can communicate will set a DTC indicating the module that cannot communicate. When no message is detected from a learned identification number for five seconds, a DTC U1xxx, where xxx is equal to the 3-digit identification number, is set.
U1040 Lost Communications With Electronic Brake Control Module (EBCM)
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Saturday, August 22nd, 2009 AT 5:42 AM

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