P1703 – Brake Switch Out of Self-Test Range (Ford)

Description

P1703 on Ford vehicles indicates that the brake pedal or stoplamp switch signal was outside the expected range during an on-demand self-test. The fault may be caused by the brake switch itself, incorrect switch adjustment, wiring or connector faults, stoplamp circuit problems or related control circuits. Diagnosis should confirm the signal and circuit fault before the switch is replaced.

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Symptoms

  • Cruise control may not operate correctly
  • Brake lights may operate incorrectly
  • P1703 may be stored after a self-test
  • Transmission or shift behavior may be affected on some vehicles
  • Other brake-switch or speed-control faults may be present
  • No obvious driving symptoms may be present

Causes

  • Open or short circuit in the brake pedal or stoplamp switch wiring
  • Faulty brake pedal or stoplamp switch
  • Incorrect brake switch adjustment
  • Blown fuse or stoplamp circuit fault
  • Damaged, loose or corroded connectors
  • Fault in the speed-control deactivator circuit on applicable vehicles
  • Control module or PCM fault in rare cases
  • Incorrect brake pedal operation during the self-test on some vehicles

Diagnosis

  • Read and record all stored fault codes
  • Check whether P1703 was stored during a KOEO or KOER self-test
  • Verify that the brake lights operate correctly
  • Monitor the brake pedal or BPP switch PID with a compatible scan tool
  • Confirm that the switch signal changes correctly when the brake pedal is pressed and released
  • Inspect the brake switch, wiring, connectors and stoplamp circuit
  • Check applicable fuses and power supply circuits
  • Check brake switch adjustment where applicable
  • Inspect the speed-control deactivator circuit on vehicles that use it
  • Repeat the self-test after repairs and confirm that P1703 does not return

Repair

  • Repair open or short circuits in the brake switch or stoplamp wiring
  • Repair damaged terminals or connectors
  • Replace a blown fuse only after the cause of the failure is identified
  • Adjust the brake switch if testing confirms incorrect adjustment
  • Replace the brake switch only if testing confirms it is faulty
  • Repair the speed-control deactivator circuit where applicable
  • Diagnose PCM or control-module faults only after external circuits have been verified

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