P1703 – Brake Switch Signal (Toyota)

Description

The ECM detected an abnormal brake switch signal affecting shift interlock and transmission control.

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Symptoms

  • Shift interlock stuck
  • Hard shifting
  • No shift from park
  • Brake lights malfunction
  • Check engine light

Causes

  • Faulty brake switch
  • Wiring issues
  • Connector corrosion
  • Misadjusted switch
  • TCM signal error

Diagnosis

  • Test brake switch
  • Inspect wiring
  • Check connectors
  • Scan TCM data
  • Verify brake light operation

Repair

  • Replace brake switch
  • Repair wiring
  • Clean connectors
  • Adjust switch

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