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Pinpoint Test A - System Inoperative

  1. Verify condition. Check all electrical and vacuum connections. Service as necessary. If connections are okay, apply brakes and observe brakelights. If brakelights do not work, repair circuit. If brakelights are okay, go to next step.
  2. Check clutch switch for proper operation (manual transmission). Service as necessary. Adjust or service throttle actuator cable as necessary. Adjust or service throttle linkage as necessary. On all models except Continental, Cougar, Sable, Taurus, and Thunderbird, go to step 5).
  3. Test vacuum check valve by disconnecting hose between check valve and servo, at servo end. Apply 18 in. Hg vacuum to check valve. If vacuum does not hold, replace check valve. If check valve is okay, check vacuum dump valve. Adjust or replace vacuum dump valve as necessary. On Cougar 3.8L SC and Thunderbird 3.8L SC, go to next step. On all other models, go to step 5).
  4. On Cougar 3.8L SC and Thunderbird 3.8L SC, check aspirator check valve. Disconnect hoses between check valves at manifold check valve end. Apply 18 in. Hg vacuum to open end of hose. Replace aspirator check valve if it does not hold vacuum. Check vacuum dump valve. See VACUUM DUMP VALVE under DIAGNOSIS & TESTING.
  5. Check for vacuum at servo. Normal servo operation requires at least 2.5 in. Hg vacuum. If vacuum is okay, go to next step. If vacuum is low, check vacuum dump valve. See VACUUM DUMP VALVE under DIAGNOSIS & TESTING. If dump valve is okay, replace leaking vacuum hose.
  6. On all models, perform CONTROL SWITCHES test under DIAGNOSIS & TESTING. If control switches are okay, perform appropriate SERVO test under DIAGNOSIS & TESTING. If servo is okay, perform VEHICLE SPEED SENSOR (VSS) test under DIAGNOSIS & TESTING. If VSS is okay, go to next step.
  7. Perform AMPLIFIER test under DIAGNOSIS & TESTING. If problem is corrected, replace amplifier. If problem is not corrected, inspect all connectors. Repair as necessary.
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