U2100 GM: CAN BUS COMMUNICATION MALFUNCTION (BUS OFF)
POST UPDATED IN May, 2023
U2100 Code failures by brands
Description of DTC code U2100
The GMLAN (General Motors Local Area Network) is an electrical system through which the various controllers installed in the vehicle are connected. Through the GMLAN, data and operating commands are sent, with which it is possible to achieve good vehicle performance. Transmission errors and reception errors are counted from the BCM (Body Control Module). The counter increases when errors are encountered and decreases when there are no error messages.
When the U2100 OBD2 diagnostic code is set on GM (General Motors) vehicles, it is because the CAN bus has experienced operational problems. The CAN bus communication has been affected, and many invalid messages have been sent on the GMLAN serial data circuits.
Symptoms of fault code U2100
- Check Engine light illuminated.
- Suspended sending messages from the controller.
Causes of OBD2 U2100
The reasons for the DTC U2100 OBDII code being set on your GM vehicle are:
- High-speed GMLAN wiring or connectors may be deficient.
- A short or open circuit could be present in the GMLAN (General Motors Local Area Network) connections.
- Damage to a control module may be present.
Possible solutions of the DTC code U2100
To troubleshoot the U2100 OBD2 fault code on General Motors manufacturer vehicles consider the following:
- Consult the Technical Service Bulletins.
- Using a scan tool, you should check for other DTCs stored with the U2100, specifically those codes that indicate problems with the Body Control Module (BCM). Perform the diagnosis based on the order of the scanner.
- Check the cables, connectors, and other components of the GMLAN high-speed circuit for common damage. Repair or replace as necessary.
- Refer to the manufacturer's steps to perform voltage checks on the system circuitry. If you detect an open or shorted circuit, make the appropriate corrections.
