U1000 - FAULT CODE - OBD2

U1000 GM: CLASS 2 COMMUNICATION MALFUNCTION CONDITIONS.

U1000 NISSAN: CAN COMMUNICATION LINE

U1000 ISUZU: CLASS 2 COMMUNICATION ID NOR LEARNED.

U1000 INFINITI: CAN COMMUNICATION LINE - SIGNAL MALFUNCTION.

The ECU (Engine Control Unit) is the vehicle’s main computer. Although it cannot communicate with a module or series of modules, it transmits commands to these devices or modules through the CAN bus (Control Area Network) so that they can perform certain tasks or functions. A vehicle is incorporated with at least two CAN bus networks, and each one of these is connected to the modules.

The Control Area Network allows sending messages at high speed to and from the Engine Control Module (ECM) and its associated modules. This makes it possible they can interact with each other. These modules have their identification code and send binary coded signals to the ECM.

When the U1000 OBDII fault code is set, it is because a class 2 communication fault was found. Note that from this code it will proceed an additional code, which identifies the module or area that has the fault.

• Check Engine light is on.
• The symptoms present are synonymous with the secondary code that refers to a specific fault, such as a faulty Climate Control Module.
• The manufacturer Nissan has a TSB, which indicates that the symptoms of this code are engine hesitation, starting problems, decreased power, among others.

Although the causes of the U1000 OBD2 diagnostic code may vary by manufacturer, these are as follows:

• On many Nissan vehicles, the U1000 code was not accompanied by another code, and because there were no operational problems, the code was ignored.
• Some vehicles indicate that the main cause of this code is the ECM.
• Other manufacturers point out that the problem is in the ground connections of the variable speed cleaner motor wiring.

The steps to solve the OBDII DTC U1000 OBDII code are:

• Consult the Technical Service Bulletins that relate to code U1000 and any additional codes.
• Identify the faulty module based on the information in the service manual and then disconnect it to isolate it from the harness and the CAN bus connector. Check these wires for damage that could cause a short or open circuit. Make the necessary repairs.