Diagnostic Trouble Code
U1000
Nissan GM Code
Technical Description U1000
GM: Class 2 Communication Malfunction Conditions Infiniti: CAN communication line - signal malfunction Isuzu: Class 2 communication ID not learned Nissan: CAN Communication Circuit
What Does This Mean U1000?
This is a manufacturer specific network code. Specific troubleshooting steps will vary depending on the vehicle.
The trouble code U1000 is a vehicle specific code primarily found on Chevrolet, GMC and Nissan vehicles. It refers to a "Class 2 communications failure." Generally, this code will precede an additional code that identifies the module or area of the failure. The second code may be generic or vehicle specific.
The electronic control unit (ECU) which is the primary computer on the vehicle is unable to communicate with a module or a series of modules. A module is simply a device that, when commanded to do so, facilitates an action or motion to occur.
The ECU relays its commands to the modules through a "CAN bus" (Controller Area Network) network of wires generally located under the carpet. There are at least two CAN bus networks on a vehicle. Each CAN bus is wired into a multitude of different modules throughout the vehicle.
The CAN bus communication network was designed by Robert Bosch and began to appear in vehicles is 2003. Since 2008, all vehicles are equipped with CAN bus networks.
The CAN bus communications network allows extremely high-speed messaging to and from the ECM and its associated modules allowing them to be interactive. Each module has its own identifying code and sends binary coded signals to the ECM.
The prefix, either a 0 or a 1 identifies the urgency or priority scale of the signal. A 0 is urgent and needs immediate response, while a 1 is less urgent and may orbit until traffic has lessened. The following codes as to the modules activity will be in binary bits seen on an oscilloscope as a squared sine wave, the height of the wave being the medium by which the ECM interpolates the signal and decides the strategy for module operation.
The trouble code U1000 is a vehicle specific code primarily found on Chevrolet, GMC and Nissan vehicles. It refers to a "Class 2 communications failure." Generally, this code will precede an additional code that identifies the module or area of the failure. The second code may be generic or vehicle specific.
The electronic control unit (ECU) which is the primary computer on the vehicle is unable to communicate with a module or a series of modules. A module is simply a device that, when commanded to do so, facilitates an action or motion to occur.
The ECU relays its commands to the modules through a "CAN bus" (Controller Area Network) network of wires generally located under the carpet. There are at least two CAN bus networks on a vehicle. Each CAN bus is wired into a multitude of different modules throughout the vehicle.
The CAN bus communication network was designed by Robert Bosch and began to appear in vehicles is 2003. Since 2008, all vehicles are equipped with CAN bus networks.
The CAN bus communications network allows extremely high-speed messaging to and from the ECM and its associated modules allowing them to be interactive. Each module has its own identifying code and sends binary coded signals to the ECM.
The prefix, either a 0 or a 1 identifies the urgency or priority scale of the signal. A 0 is urgent and needs immediate response, while a 1 is less urgent and may orbit until traffic has lessened. The following codes as to the modules activity will be in binary bits seen on an oscilloscope as a squared sine wave, the height of the wave being the medium by which the ECM interpolates the signal and decides the strategy for module operation.
Symptoms U1000
1
If the U1000 stands alone, no symptoms may be present
2
Symptoms will likely be present synonymous with the secondary code indicating a particular failure-a failed climate control module or a failed automatic headlight-dimming module for example
3
In the case of a known Nissan TSB (technical service bulletin), symptoms may include engine stalling, hesitation, lack of power, failure to start or other potential symptoms.