LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2002 >> ZX2 Standard >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Shift Interlock System >> System Tests >> Pinpoint Test A (Focus) >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

NOTE: Brake Pedal Position (BPP) switch is also referred to as brakelight switch.
  1. Turn ignition switch to ON position. Depress brake pedal. Are the brakelights ON? If so, go to step  5. If not, go to next step.
  2. Measure resistance in fuse No. 42 (15-amp), located in Central Junction Box (CJB). Is fuse No. 42 okay? If so, go to next step. If not, replace fuse No. 42 and recheck system. If fuse fails again, repair short to ground in Green/White wire.
  3. Turn ignition switch to OFF position. Disconnect brakelight switch harness connector. Turn ignition switch to ON position. Measure voltage at brakelight switch harness connector terminal No. 3. Is voltage greater than 10 volts? If so, go to next step. If not, repair open in Green/White wire. Reconnect all components and test the system for normal operation.
  4. Measure the resistance of the brakelight switch while open (OFF) and closed (ON). Is the resistance of switch greater than 10 k/ohms while OFF, and 5 ohms or less while ON? If so, go to next step. If not, replace brakelight switch and test the system for normal operation. See BRAKE PEDAL POSITION SWITCH  under REMOVAL & INSTALLATION.
  5. Turn ignition switch to ON position. Place gearshift in Park position. Can ignition switch be turned to OFF position and can key be removed only when gear selector in Park? If so, go to next step. If not, go to step  10.
  6. Turn ignition switch to OFF position. Disconnect gearshift lever unit harness connector. Measure the voltage between gearshift lever unit harness connector terminal No. 3 and ground. See Fig 1. Is the voltage zero volts when brake pedal is not depressed, and battery voltage when brake pedal is depressed? If so, go to next step. If not, repair open between gearshift lever unit and brakelight switch.
  7. Measure resistance between gearshift lever unit harness connector terminal No. 1 and ground. See Fig 2. Is resistance less than 5 ohms? If so, go to next step. If not, repair open in Black wire and test the system for normal operation.
  8. Measure resistance at the gearshift lever unit terminals No. 1 and 3 (component side). Place gearshift lever in Park position. Is resistance between 20 and 35 ohms? If so, go to next step. If not, replace shift interlock actuator. See SHIFT INTERLOCK ACTUATOR  under REMOVAL & INSTALLATION. After repairs, test the system for normal operation.
  9. Position gearshift lever into Reverse, Neutral, Drive, 1 and 2 positions. If necessary, release gearshift mechanically. See DESCRIPTION & OPERATION . Is resistance greater than 10 ohms in all mentioned positions? If so, shift interlock actuator is electrically okay. Check for mechanical fault. If not, replace shift interlock actuator. See SHIFT INTERLOCK ACTUATOR  under REMOVAL & INSTALLATION. After repairs, test the system for normal operation.
  10. Measure resistance in fuse No. 8 (20-amp), located in CJB. Is the fuse No. 8 (20-amp) okay? If so, go to next step. If not, replace fuse and recheck the system.
  11. Disconnect gearshift lever unit harness connector. Connect a jumper wire between gearshift lever unit harness connector terminal No. 2 and ground. See Fig 3. Be sure that only terminal No. 2 and not another pin is grounded. Can ignition key be removed when jumper wire is connected? If so, go to next step. If not, go to step  13.
  12. Measure resistance between gearshift lever unit harness connector terminal No. 1 and ground. See Fig 2. Is resistance less than 5 ohms? If so, replace the gearshift lever unit. See GEARSHIFT LEVER UNIT  under REMOVAL & INSTALLATION. After repairs, test the system for normal operation. If not, repair open in Black wire and test the system for normal operation.
  13. Measure voltage at fuse No. 8 (20-amp). Is battery voltage indicated? If so, go to next step. If not, repair open in battery feed circuit.
  14. Turn ignition switch to OFF position. Disconnect ignition switch harness connector. Measure the voltage between ignition switch harness connector terminal No. 4 and ground. See Fig 4. Is battery voltage indicated? If so, go to next step. If not, repair open in Red wire and test the system for normal operation.
  15. Measure resistance between ignition switch harness connector terminal No. 3 and gearshift lever unit harness connector terminal No. 2. See Fig 5. Is resistance less than one ohm? If so, key removal inhibit solenoid within the ignition switch is damaged. Replace the ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If not, repair open in Black/Yellow wire and test the system for normal operation.
Fig 1: Measuring Voltage At Gearshift Lever Unit
G00104233Courtesy of FORD MOTOR CO.
Fig 2: Checking Ground Circuit at Gearshift Lever Unit
G00104234Courtesy of FORD MOTOR CO.
Fig 3: Jumping Terminal No. 2 To Ground At Gearshift Lever Unit
G00104238Courtesy of FORD MOTOR CO.
Fig 4: Measuring Voltage At Ignition Switch
G00104236Courtesy of FORD MOTOR CO.
Fig 5: Measuring Resistance Between Ignition Switch & Gearshift Lever Unit
G00104237Courtesy of FORD MOTOR CO.
scientia non olet · About LEMON Manuals