U1001 - FAULT CODE - OBD2

The CAN bus (Control Area Network) is a serial communication line or network for vehicles in real-time. Data regarding vehicle operation is transmitted through this communication network at the right speed. Take into account this network has a high error detection capacity.

The control modules installed in the vehicle share information with each other, and link with other control units during operation time. During the information exchange, the units are connected with 2 communication lines. The CAN H line and CAN L line allow a high speed of information transmission with a smaller number of cables. Although each unit transmits and receives data, it uses a required selection process to read the data.

When the U1001 OBDII fault code is set, it is because the ECM (Engine Control Module) is not receiving or transmitting the OBDII communication signal related to the emission system for more than 2 seconds.

• Check Engine lamp illuminates.

Reasons for setting the U1001 OBD2 diagnostic code:

• The Controller Area Network (CAN) wiring may have damage, causing a short or open circuit.
• The ECM ground harness could have deficiencies.
• The ECM could be defective.

Steps to take to fix the DTC U1001 OBDII code:

• First, it is necessary to consult the vehicle's information source to be aware of the Technical Service Bulletins.
• Taking into account the information indicated in the service manual, locate the CAN bus wiring, and verify that they do not present common damages. Replace any burnt, worn, or corroded wiring.
• Check the Engine Control Module wiring to verify that it is in good condition. If they show inconsistencies due to corrosion, wear, or any other reason, make the necessary corrections. If the connections are OK, go to a specialized service center for more complex diagnostic steps.