Hours: 07–23 daily
EN
Tune your file

TuningBot DTC Database · v4.37.15

U01B4 Lost Communication With Brake System Control Module B

Generic (OBD-II) interpretation in the TuningBot DTC database.

U · NetworkNetworkOBD2

What U01B4 means

U01B4
Lost Communication With Brake System Control Module B Generic · network Data confidence 65%

The control module stopped receiving expected network messages from the Brake System Control Module B node on the vehicle communication bus.

Symptoms

  • Multiple warning lamps possible
  • Functions of the affected module unavailable

Possible causes

  • CAN bus wiring fault (open, short, chafed harness)
  • Faulty control module loading the bus
  • Connector or terminal corrosion
  • Power supply or ground fault of a module

Recommended checks

  • Perform a full-module scan to map which modules communicate
  • Check CAN bus resistance and voltages at the diagnostic connector
  • Inspect wiring and connectors of the affected module
  • Check module power supply and grounds
  • Disconnect suspect modules one at a time only with a documented procedure

Related and nearby codes

U01 range
U0100U0101U0102U0103U0104U0105U0106U0107U0108U0109U010AU010BU010CU010DU010EU010FU0110U0111

How to read U01B4

U

Network: communication between control units.

0

Generic SAE-standard code: same meaning on every make.

1B4

Specific fault index within the subsystem.

Frequently asked questions about U01B4

What does U01B4 mean?

Lost Communication With Brake System Control Module B. The control module stopped receiving expected network messages from the Brake System Control Module B node on the vehicle communication bus.

Is U01B4 generic or manufacturer-specific?

U01B4 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U01B4 at file level?

Not guaranteed. Powertrain (P) codes can be reliably disabled in the ECU calibration, but body, chassis and network codes depend on the specific control unit and how the fault is implemented - some can be handled, some cannot. Ask for a quote and our engineers will check your file and tell you, free of charge, whether U01B4 is removable in your case.

Other file services

Stage 1/2/3 TuningDPF RemovalEGR RemovalAdBlue / SCR RemovalDTC RemovalIMMO OFFSpeed Limiter (Vmax)

Understand the system behind this code: Diagnostic Strategy and DTC Logic

ECU tuningDyno-tested results by model and engine See the results →

← Search the full DTC database