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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1018 (Cruise Control System (F-250-F550)) >> Diagnostic Tests >> Speed Control >> Pinpoint Tests >> Pinpoint Test C: DTC P1703 Or DTC P1572 - Brake On/Off Circuit Failure >> Pinpoint Test C: DTC P1703 Or DTC P1572 - Brake On/Off Circuit Failure

Pinpoint Test C: DTC P1703 Or DTC P1572 - Brake On/Off Circuit Failure

WARNING: This page is about a different car, the 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. C1 CHECK CIRCUIT 810 (RD/LG) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: PCM C175b (Gasoline) or C1381a (Diesel)
    • Key in ON position.
    • For gasoline vehicles, measure the voltage between the PCM C175b-8, circuit 810 (RD/LG), harness side and ground.
      • Fig 1: Checking Circuit 810 (RD/LG) For Voltage (1 Of 2)
      G03889838Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the voltage between the PCM C1381a-18, circuit 810 (RD/LG), harness side and ground.
      • Fig 2: Checking Circuit 810 (RD/LG) For Voltage (2 Of 2)
      GF0007697Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : Go to  C2.
    2. NO  : Go to  C5.
  2. C2 CHECK THE STOPLAMP SWITCH 
    • Key in OFF position.
    • Disconnect: Stoplamp Switch C278
    • Key in ON position.
    • For gasoline vehicles, measure the voltage between the PCM C175b-8, circuit 810 (RD/LG), harness side and ground.
      • Fig 3: Checking Stoplamp Switch (1 Of 2)
      G03889838Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the voltage between the PCM C1381a-18, circuit 810 (RD/LG), harness side and ground.
      • Fig 4: Checking Stoplamp Switch (2 Of 2)
      GF0007697Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : If equipped with an automatic transmission, go to  C3 .

      If equipped with four-wheel drive (4WD) and a manual transmission, go to  C4 .

      If equipped with two-wheel drive (2WD) and a manual transmission, go to  C5 .

    2. NO  : INSTALL a new stoplamp switch. REFER to EXTERIOR LIGHTING article. CLEAR the DTCs. REPEAT the self-test.
  3. C3 CHECK THE BRAKE SHIFT INTERLOCK ACTUATOR 
    • Key in OFF position.
    • Disconnect: Brake Shift Interlock C2008
    • Key in ON position.
    • For gasoline vehicles, measure the voltage between the PCM C175b-8, circuit 810 (RD/LG), harness side and ground.
      • Fig 5: Checking Brake Shift Interlock Actuator (1 Of 2)
      G03889838Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the voltage between the PCM C1381a-18, circuit 810 (RD/LG), harness side and ground.
      • Fig 6: Checking Brake Shift Interlock Actuator (2 Of 2)
      GF0007697Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : If equipped with 2WD and a manual transmission, REPAIR circuit 810 (RD/LG). CLEAR the DTCs. REPEAT the self-test.

      If equipped with 4WD and a manual transmission, go to  C4 .

    2. NO  : INSTALL a new brake shift interlock actuator. REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - TORQSHIFT article. CLEAR the DTCs. REPEAT the self-test.
  4. C4 CHECK THE 4WD CONTROL MODULE 
    • Key in OFF position.
    • Disconnect: 4WD Control Module C281a
    • Key in ON position.
    • For gasoline vehicles, measure the voltage between the PCM C175b-8, circuit 810 (RD/LG), harness side and ground.
      • Fig 7: Checking 4WD Control Module (1 Of 2)
      G03889838Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the voltage between the PCM C1381a-18, circuit 810 (RD/LG), harness side and ground.
      • Fig 8: Checking 4WD Control Module (2 Of 2)
      GF0007697Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : REPAIR circuit 810 (RD/LG). CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C12.
  5. C5 CHECK THE STOPLAMP SWITCH FOR CORRECT OPERATION 
    • For gasoline vehicles, while applying the brake pedal, measure the voltage between the PCM C175b-8, circuit 810 (RD/LG), harness side and ground.
      • Fig 9: Checking Stoplamp Switch For Correct Operation (1 Of 2)
      G03889838Courtesy of FORD MOTOR CO.
    • For diesel vehicles, while applying the brake pedal, measure the voltage between the PCM C1381a-18, circuit 810 (RD/LG), harness side and ground.
      • Fig 10: Checking Stoplamp Switch For Correct Operation (2 Of 2)
      GF0007697Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  C8.
    2. NO  : Go to  C6.
  6. C6 CHECK CIRCUIT 22 (LB/BK) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Stoplamp Switch C278
    • Key in ON position.
    • Measure the voltage between the stoplamp switch C278-3, circuit 22 (LB/BK), harness side and ground.
      • Fig 11: Checking Circuit 22 (LB/BK) For Open
      GF0007698Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  C7.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  7. C7 CHECK CIRCUIT 810 (RD/LG) FOR AN OPEN 
    • Key in OFF position.
    • For gasoline vehicles, measure the resistance between the stoplamp switch C278-4, circuit 810 (RD/LG), harness side and the PCM C175b-8, circuit 810 (RD/LG), harness side.
      • Fig 12: Checking Circuit 810 (RD/LG) For Open (1 Of 2)
      GF0007699Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the resistance between the stoplamp switch C278-4, circuit 810 (RD/LG), harness side and the PCM C1381a-18, circuit 810 (RD/LG), harness side.
      • Fig 13: Checking Circuit 810 (RD/LG) For Open (2 Of 2)
      GF0007700Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    1. YES  : INSTALL a new stoplamp switch. REFER to EXTERIOR LIGHTING article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  8. C8 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH FOR CORRECT OPERATION 
    • For gasoline vehicles, while firmly applying and releasing the brake pedal, measure the voltage between the PCM C175a-65, circuit 307 (BK/YE), harness side and ground.
      • Fig 14: Checking Speed Control Deactivator Switch For Correct Operation (1 Of 2)
      GF0007701Courtesy of FORD MOTOR CO.
    • For diesel vehicles, while firmly applying and releasing the brake pedal, measure the voltage between the PCM C1381a-28, circuit 307 (BK/YE), harness side and ground.
      • Fig 15: Checking Speed Control Deactivator Switch For Correct Operation (2 Of 2)
      GF0007702Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts with the brake pedal released, and 0 volts with the brake pedal firmly applied? 
    1. YES  : Go to  C13.
    2. NO  : Go to  C9.
  9. C9 CHECK CIRCUIT 418 (DG/YE) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Speed Control Deactivator Switch C1025
    • Key in ON position.
    • Measure the voltage between the speed control deactivator switch C1025-1, circuit 418 (DG/YE), harness side and ground.
      • Fig 16: Checking Circuit 418 (DG/YE) For An Open
      GF0006743Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  C10.
    2. NO  : VERIFY the central junction box (CJB) fuse 12 (2A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  10. C10 CHECK CIRCUIT 307 (BK/YE) FOR A SHORT TO VOLTAGE 
    • Measure the voltage between the speed control deactivator switch C1025-2, circuit 307 (BK/YE), harness side and ground.
      • Fig 17: Checking Circuit 307 (BK/YE) Short To Voltage
      GF0006742Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C11.
  11. C11 CHECK CIRCUIT 307 (BK/YE) FOR AN OPEN 
    • Key in OFF position.
    • For gasoline vehicles, measure the resistance between the speed control deactivator switch C1025-2, circuit 307 (BK/YE), harness side and the PCM C175a-65, circuit 307 (BK/YE), harness side.
      • Fig 18: Checking Circuit 307 (BK/YE) For An Open (1 Of 2)
      GF0007703Courtesy of FORD MOTOR CO.
    • For diesel vehicles, measure the resistance between the speed control deactivator switch C1025-2, circuit 307 (BK/YE), harness side and the PCM C1381a-28, circuit 307 (BK/YE), harness side.
      • Fig 19: Checking Circuit 307 (BK/YE) For Open (2 Of 2)
      GF0007704Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    1. YES  : INSTALL a new speed control deactivator switch. REFER to Speed Control Deactivator Switch  in this article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  12. C12 CHECK FOR CORRECT 4WD CONTROL MODULE OPERATION 
    • Disconnect all the 4WD control module connectors.
    • Check for:
      • corrosion
      • pushed-out pins
    • Connect all the 4WD control module connectors and make sure they are seated correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new 4WD control module. REFER to FOUR WHEEL DRIVE (4WD) SYSTEMS article.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
  13. C13 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion
      • pushed-out pins
    • Connect all the PCM connectors and make sure they are seated correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS - GASOLINE ENGINES article.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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