What does code U01B7 mean?

Q: What does code U01B7 mean?

Lost Communication With Switch Input Module A. U01B7 is a generic network communication code indicating that a control module on the vehicle's data bus has lost contact with the Switch Input Module A, which is the module that reads inputs from switches such as steering wheel buttons, console switches, or door-mounted controls. The computer detected that expected periodic messages from that module stopped arriving within the required time window, so it flagged the module as missing rather than reporting a faulty switch itself.

DTC codes / U01xx · Lost communication with a control module / U01B7

U01B7Lost Communication With Switch Input Module A

U01B7 is a generic network communication code indicating that a control module on the vehicle's data bus has lost contact with the Switch Input Module A, which is the module that reads inputs from switches such as steering wheel buttons, console switches, or door-mounted controls. The computer detected that expected periodic messages from that module stopped arriving within the required time window, so it flagged the module as missing rather than reporting a faulty switch itself.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaLost communication with a control module

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.