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Pinpoint Test C

NOTE: Pinpoint Test C has been revised due to Ford Technical Service Bulletin 90-18B-5.

Enter pinpoint test only when service Codes 81 or 82 are received in the KEY ON, ENGINE OFF SELF-TEST. This pinpoint test is intended to diagnose only the servo vent solenoid, servo vacuum solenoid, circuits SOL+, SCVNT, SCVAC, and the ECA.

  1. Turn key off. Disconnect ECA 60-pin connector. Inspect for damage. Service as necessary. Install Breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin 13 and test pin 35. If resistance is 100-150 ohms, and code 82 is present go to Step 6) otherwise go to Step 4). If resistance is less than 100 ohms, replace servo and repeat QUICK TEST. If resistance is greater than 150 ohms, go to Step 2).
  2. Disconnect harness connector from servo. Set DVOM on 200-ohm scale. Measure resistance between test pin 13 and SOL+ circuit at harness connector. If resistance is greater than 5 ohms, service open circuit and repeat QUICK TEST. If resistance is less than 5 ohms, go to Step 3).
  3. Disconnect harness connector from servo. Set DVOM on 200-ohm scale. Measure resistance between test pin 35 and SCVNT circuit at harness connector. If resistance is greater than 5 ohms, service open circuit and repeat QUICK TEST. If resistance is less than 5 ohms, replace servo and repeat QUICK TEST.
  4. Disconnect harness connector from servo. Set DVOM on 200,000-ohm scale. Measure resistance between SOL+ and test pin 60 (ground). If the resistance is greater than 10,000 ohms go to Step 5).If the resistance is less than 10,000 ohms SERVICE the shorted circuit and repeat the QUICK TEST (the short may have caused damage to the ECA).
  5. Disconnect harness connector from servo. Set DVOM on 200,000-ohm scale. Measure resistance between SCVNT and test pin 60 (ground). If the resistance is greater than 10,000 ohms replace the ECA and repeat QUICK TEST. If the resistance is less than 10,000 ohms SERVICE the shorted circuit and repeat the QUICK TEST .
  6. Turn key off. Disconnect ECA 60-pin connector. Inspect for damage. Service as necessary. Install Breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin 13 and test pin 42. If resistance is 40-75 ohms, go to Step 9). If resistance is less than 40 ohms, replace servo and repeat QUICK TEST. If resistance is greater than 75 ohms, go to Step 7).
  7. Disconnect harness connector from servo. Set DVOM on 200-ohm scale. Measure resistance between test pin 13 and SOL+ circuit at harness connector. If resistance is greater than 5 ohms, service open circuit and repeat QUICK TEST. If resistance is less than 5 ohms, go to Step 8).
  8. Disconnect harness connector from servo. Set DVOM on 200-ohm scale. Measure resistance between test pin 42 and SCVAC circuit at harness connector. If resistance is greater than 5 ohms, service open circuit and repeat QUICK TEST. If resistance is less than 5 ohms, replace the servo and repeat QUICK TEST. See Fig 1.
  9. Disconnect harness connector from servo. Set DVOM on 200,000-ohm scale. Measure resistance between SOL+ and test pin 60 (ground). If the resistance is greater than 10,000 ohms go to Step 10).If the resistance is less than 10,000 ohms SERVICE the shorted circuit and repeat the QUICK TEST (the short may have caused damage to the ECA).
  10. Disconnect harness connector from servo. Set DVOM on 200,000-ohm scale. Measure resistance between SCVAC and test pin 60 (ground). If the resistance is greater than 10,000 ohms replace the ECA and repeat QUICK TEST. If the resistance is less than 10,000 ohms SERVICE the shorted circuit and repeat the QUICK TEST .
Fig 1: Pinpoint Test C Wiring Diagram
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