Pinpoint Test B: DTC P1703 or DTC P1572 -Brake On/Off Circuit Failure: Testing

B1 CHECK THE STOPLAMPS
- Verify the stoplamps operate correctly.
- Do the stop lamps operate correctly?
- Yes : GO to B2.
- No : REFER to EXTERIOR LIGHTING to continue diagnosis of the stop lamps.
B2 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH FOR CORRECT OPERATION
- Key in OFF position.
- Disconnect: PCM C175b.
- Key in ON position.
- While firmly applying and releasing the brake pedal, measure the voltage between the PCM C175b-7, circuit 307 (BK/YE), harness side and ground.
  
  Fig 1: Checking Speed Control Deactivator Switch For Correct Operation
  Courtesy 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?
- Yes : GO to B6.
- No : GO to B3.
B3 CHECK CIRCUIT 1140 (VT) FOR AN OPEN
- Key in OFF position.
- Disconnect: Speed Control Deactivator Switch C2227.
- Key in ON position.
- Measure the voltage between the speed control deactivator switch C2227-2, circuit 1140 (VT), harness side and ground.
  
  Fig 2: Checking Circuit 1140 (VT) For An Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to B4.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
B4 CHECK CIRCUIT 307 (BK/YE) FOR A SHORT TO POWER
- Measure the voltage between the speed control deactivator switch C2227-1, circuit 307 (BK/YE), harness side and ground.
  
  Fig 3: Checking Circuit 307 (BK/YE) For Short To Power
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
- No : GO to B5.
B5 CHECK CIRCUIT 307 (BK/YE) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the speed control deactivator switch C2227-1, circuit 307 (BK/YE), harness side and the PCM C175b-7, circuit 307 (BK/YE), harness side.
  
  Fig 4: Checking Circuit 307 (BK/YE) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new speed control deactivator switch. REFER to SPEED CONTROL DEACTIVATOR SWITCH . CLEAR the DTCs. REPEAT the self-test.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
B6 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?
- Yes : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS .
- 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.