LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2004 >> Mustang Base, 2D Convertible, 3.8 4, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor Through Pinpoint Test HC: Fuel Delivery System - CNG, Flex-Fuel & Gasoline >> Pinpoint Test FD: Brake Pedal Inputs >> Test Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Procedure

  1. FD1 KOER DTCS P0703 AND P1703: VERIFY THE BRAKE PEDAL WAS APPLIED 

    Was the brake pedal applied and released during the KOER self-test? 

    Yes No
    GO to  FD3. Rerun the KOEO self-est.
    Apply and release the brake pedal during the KOER test.
  2. FD2 KOEO DTC P0703, P1703: VERIFY THE BRAKE PEDAL WAS NOT APPLIED 

    Was the brake pedal applied during the KOEO self-test? 

    Yes No
    Rerun the KOEO self-est.
    Avoid applying the brake pedal during the KOEO test.    		 GO to  FD3.
  3. FD3 DTCS P0703, P1572 AND P1703: CHECK THE OPERATION OF THE STOPLAMPS 
    NOTE: CHECK the condition of the stoplamp bulbs before starting this test.
    • Key ON Engine OFF.
    • Apply and release the brake pedal several times and observe the stoplamp operation.

    Do the stoplamps operate normally? 

    Yes No
    GO to  FD6. GO to  FD4.
  4. FD4 CHECK IF THE APPLICATION USES STABILITY ASSIST 
    • For the following vehicles with Stability Assist:
      • Focus.
      • Lincoln LS6 and LS8.
      • Thunderbird.
      • Aviator and Explorer/Mountaineer.

    Is vehicle equipped with stability assist and listed above? 

    Yes No
    REFER to the appropriate EXTERIOR LIGHTING article for further stoplamp diagnosis. GO to  FD5.
  5. FD5 CHECK FOR STOPLAMPS ALWAYS ON OR ALWAYS OFF 
    • Apply and release the brake pedal several times and observe the stoplamp operation.
    NOTE: This step addresses always on or always off operation. For intermittent operation. GO to PINPOINT TEST Z step 1 .

    Are the stoplamps always ON? 

    Yes No
    GO to  FD14. GO to  FD9.
  6. FD6 CHECK FOR BPP PID AVAILABILITY 
    • Scan tool connector connected.
    • Access the PCM -BPP/BOO PID.

    Is the BPP PID available? 

    Yes No
    GO to  FD7. GO to  FD23.
  7. FD7 CHECK FOR PCM BPP PID CYCLING 
    • Apply and release the brake pedal several times while viewing the BPP PID.

    Does the BPP PID cycle ON and OFF? 

    Yes No
    GO to  FD8. GO to  FD9.
  8. FD8 DTC P1572 IS PRESENT 

    Is DTC P1572 present? 

    Yes No
    GO to  FD23. KEY OFF.
    Unable to duplicate or identify the fault at this time.
    GO to PINPOINT TEST Z step 1 .
  9. FD9 CHECK THE B+ VOLTAGE TO THE BPP SWITCH 
    • BPP Switch connector disconnected.
    • Measure the voltage between:
    ( + )BPP Switch Connector, Harness Side ( - )
    B+ Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to  FD10. VERIFY the integrity of the fuse for the B+ to BPP switch. If OK, REPAIR the open in the B+ circuit. If fuse is damaged, check the B+ circuit, BPP circuit, stoplamp PWR circuit and any other associated circuits for a short to ground. REFER to the appropriate SYSTEM WIRING DIAGRAMS article. REPAIR as necessary.
  10. FD10 CHECK THE APPLICATION FOR GROUND TO THE BPP SWITCH 
    • The following vehicles have a ground to the BPP switch.
      • F-Series Super Duty.
      • Excursion.

    Is vehicle listed above? 

    Yes No
    GO to  FD11. GO to  FD13.
  11. FD11 CHECK GROUND TO THE BPP SWITCH 
    • Measure the resistance between:
    ( + )BPP Switch Connector, Harness Side ( - )
    GND Ground

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  FD12. REPAIR open circuit.
  12. FD12 VERIFY THE INTEGRITY OF THE BPP SWITCH - NORMALLY CLOSED SWITCH CONTACTS 
    • Do not apply the break pedal while observing the resistance measurement.
    • Measure the resistance between:
    ( + )BPP Switch Connector, Harness Side ( - )BPP Switch Connector, Harness Side
    GND BPP

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  FD13. INSTALL a new BPP switch.
  13. FD13 VERIFY THE INTEGRITY OF THE BPP SWITCH - NORMALLY OPEN SWITCH CONTACTS 
    • Apply the brake pedal and observe the resistance measurement.
    • Measure the resistance between:
    ( + )BPP Switch Connector, Component Side ( - )BPP Switch Connector, Component Side
    B+ BPP

    Is the resistance less than 5 ohms? 

    Yes No
    REPAIR open circuit.
    Between the BPP switch and stoplamp ground.    		 INSTALL a new BPP switch.
  14. FD14 VERIFY THE BPP SWITCH IS NOT ALWAYS CLOSED 
    • BPP Switch connector disconnected.
    • Key ON Engine OFF.

    Are the stoplamps still on? 

    Yes No
    KEY OFF.
    GO to  FD15.    		 Verify proper installation of the BPP switch.
    If OK, install a new BPP switch.
  15. FD15 CHECK FOR SHORT TO POWER IN THE PCM 
    • PCM connector disconnected.
    • Key ON Engine OFF.

    Are the stoplamps still on? 

    Yes No
    GO to  FD16. KEY OFF. INSTALL a new PCM.
    Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .
  16. FD16 CHECK THE STOPLAMP CIRCUIT FOR A SHORT TO POWER IN THE HARNESS 
    • One at a time, DISCONNECT all modules associated with the stoplamp circuit. REFER to the appropriate SYSTEM WIRING DIAGRAMS article. After disconnecting each module, turn the key to the ON position and observe the stoplamps. Turn the key to the OFF position. Repeat until each associated module is disconnected or the stoplamps turn off.

    Did the stoplamps turn off when any of the modules were disconnected? 

    Yes No
    REFER to the appropriate article for further diagnosis of the appropriate module. REPAIR short circuit to PWR.
  17. FD17 CHECK IF THE APPLICATION USES STABILITY ASSIST 
    • For the following vehicles with Stability Assist:
      • Focus.
      • Lincoln LS6 and LS8.
      • Thunderbird.
      • Aviator and Explorer/Mountaineer.

    Is vehicle equipped with stability assist and listed above? 

    Yes No
    GO to  FD18. GO to  FD19.
  18. FD18 CHECK FOR BPP CIRCUIT CYCLING 
    • PCM connector disconnected.
    • Apply and release the brake pedal and observe the voltage measurement.
    • Measure the voltage between:
    ( + )PCM Connector, Harness Side ( - )
    BPP Ground

    Does the voltage cycle? 

    Yes No
    GO to  FD20. KEY OFF. REPAIR open circuit.
  19. FD19 CHECK FOR BPP CIRCUIT CYCLING 
    • PCM connector disconnected.
    • Apply and release the brake pedal and observe the voltage measurement.
    • Measure the voltage between:
    ( + )PCM Connector, Harness Side ( - )
    BPP Ground

    Does the voltage cycle? 

    Yes No
    KEY OFF. INSTALL a new PCM.
    Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .    		 KEY OFF. REPAIR open circuit.
  20. FD20 CHECK FOR A BPA CIRCUIT CYCLING 
    • PCM connector disconnected.
    • Apply and release the brake pedal and observe the voltage measurement.
    • Measure the voltage between:
    ( + )PCM Connector, Harness Side ( - )
    BPA Ground

    Does the voltage cycle? 

    Yes No
    GO to  FD25. GO to  FD21.
  21. FD21 CHECK THE BPA CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Disconnect the BPA deactivator switch.
    • Measure the resistance between:
    ( + )BPA Switch Connector, Harness Side ( - )PCM Connector, Harness Side
    BPA BPA

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  FD22. REPAIR open circuit.
  22. FD22 CHECK THE BPA CIRCUIT FOR POWER 
    • Measure the voltage between:
    ( + )BPA Switch Connector, Harness Side ( - )
    B+ Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    KEY OFF. INSTALL a new BPA switch. KEY OFF. REPAIR open circuit.
  23. FD23 CHECK FOR BPA PID AVAILABILITY 
    • Scan tool connector connected.
    • Access the PCM -BPA PID.

    Is the BPA PID available? 

    Yes No
    GO to  FD24. GO to  FD17.
  24. FD24 CHECK FOR PCM BPA SWITCH PID CYCLING 
    • Key ON Engine RUN.
    • Access the PCM -BPA PID.
    • Apply and release the brake pedal several times while viewing the BPA PID.

    Does the BPA PID cycle ON and OFF? 

    Yes No
    KEY OFF.
    GO to  FD19.    		 GO to  FD20.
  25. FD25 BPP AND BPA RATIONALITY CHECK 
    • Reconnect all the disconnected components.
    • CLEAR the DTCs.
    • Key ON Engine RUN.
    • Apply and release the break pedal several times.
    • Retrieve Continuous Memory DTCs

    Is DTC P1572 present? 

    Yes No
    CHECK for a misadjusted brake switch (BPP or BPA). REPAIR as necessary. GO to  FD26.
  26. FD26 CHECK THE PCM FOR REOCCURRING BRAKE PEDAL DTCS 
    • Rerun the KOEO self-est.
    • CHECK Self-Test DTCs:

    Are DTCs P0703 or P1703 present? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM . KEY OFF.
    Test Complete
scientia non olet · About LEMON Manuals