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TuningBot DTC Database · v4.37.15

U01B9 Lost Communication With Switch Input Module “C”

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

U · NetworkNetworkOBD2

What U01B9 means

U01B9
Lost Communication With Switch Input Module “C” Generic · network Data confidence 65%

The control module stopped receiving expected network messages from the Switch Input Module “C” 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 U01B9

U

Network: communication between control units.

0

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

1B9

Specific fault index within the subsystem.

Frequently asked questions about U01B9

What does U01B9 mean?

Lost Communication With Switch Input Module “C”. The control module stopped receiving expected network messages from the Switch Input Module “C” node on the vehicle communication bus.

Is U01B9 generic or manufacturer-specific?

U01B9 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U01B9 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 U01B9 is removable in your case.

Other file services

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