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TuningBot DTC Database · v4.37.15

U0103 Data bus: gear shift module - no communication / System relay - low signal

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

U · NetworkNetworkOBD2

What U0103 means

U0103
Data bus: gear shift module - no communication / System relay - low signal Generic · network Data confidence 65%

The control module did not receive the expected response for Data bus: gear shift module within the allowed time.

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
U0100U0101U0102U0104U0105U0106U0107U0108U0109U010AU010BU010CU010DU010EU010FU0110U0111U0112

How to read U0103

U

Network: communication between control units.

0

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

103

Specific fault index within the subsystem.

Frequently asked questions about U0103

What does U0103 mean?

Data bus: gear shift module - no communication / System relay - low signal. The control module did not receive the expected response for Data bus: gear shift module within the allowed time.

Is U0103 generic or manufacturer-specific?

U0103 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U0103 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 U0103 is removable in your case.

Other file services

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