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U0038 Network

Vehicle Communication Bus B Performance

Bus B is electrically OK but message rate or error counters are outside spec. Often intermittent wiring or a degraded transceiver.

Affected components

  • Bus b wiring

Common causes

  • High likelihood: Wiring chafed or marginal
  • Low likelihood: Gateway module routing CAN messages incorrectly
  • Low likelihood: CAN terminating resistor (120 Ω) drifted out of spec

Possible symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • A drive cycle may be required after repair

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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