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Circuit Test E - Anti-Lock Light Intermittently On

  1. Fluid Level Sensor & Pressure Warning Switch Circuit Check Unplug 32-pin connector from ECM. Connect Breakout Box (T83L-50-EEC-IV) and Adapter (T87P-50-ALA) to connector. Turn ignition on. Using an ohmmeter, check resistance between breakout box pins No. 25 and No. 27. If resistance is less than 5 ohms, go to step 7). If resistance is more than 5 ohms, go to step 2).
  2. Fluid Level Sensor Anti-Lock Warning Circuit Check Unplug 5-pin connector from fluid level sensor. Using an ohmmeter, measure resistance between fluid level sensor connector pins No. 1 and No. 2 with brake fluid at maximum level. If resistance is greater than 2 ohms, replace fluid level sensor. If resistance is 2 ohms or less, go to step 3).
  3. Pressure Warning Switch Anti-Lock Warning Circuit Check (No Pressure) Turn ignition off. Depressurize brake system by turning ignition off and pumping brake pedal at least 20 times until pedal becomes hard. Unplug 5-pin connector from pressure warning switch. Using an ohmmeter, check continuity between pressure warning switch pins No. 3 and No. 5. If continuity exists, replace pressure warning switch and pump/motor relay. If no continuity exists, go to step 4).
  4. Fluid Level Sensor-To-ECM Circuit Check Using an ohmmeter, check for continuity between breakout box pin No. 25 and fluid level sensor connector pin No. 1. If no continuity exists, repair circuit No. 512A (No. 512 on Mark VII). If continuity exists, go to step 5).
  5. Fluid Level Sensor-To-Pressure Warning Switch Circuit Check Using an ohmmeter, check for continuity between fluid level sensor connector pin No. 2 and pressure warning switch connector pin No. 3. If no continuity exists, repair circuit No. 549A (No. 549 on Mark VII). If continuity exists, go to step 6).
  6. Pressure Warning Switch-To-ECM Circuit Check Using an ohmmeter, check for continuity between pressure warning switch connector pin No. 5 and breakout box pin No. 27. If no continuity exists, repair circuit No. 535A (No. 535 on Mark VII). If continuity exists, turn ignition off. Reconnect all connections. Reverify symptom.
  7. Fluid Level Sensor & Pressure Warning Switch Isolation Check Check for continuity between breakout box pin No. 25 and ground. If no continuity exists, reverify symptom. If continuity exists, go to step 8).
  8. Fluid Level Sensor Continuity Check Unplug fluid level sensor connector. Using an ohmmeter, check for continuity between sensor pin No. 1 and pins No. 3, No. 4, and No. 5. Also check between pin No. 2 and pins No. 3, No. 4, and No. 5. If continuity exists, replace fluid level sensor. If no continuity exists, go to step 9).
  9. Continuity of Fluid Level Sensor Pin No. 1 Circuit Check Using an ohmmeter, check continuity between fluid level sensor connector pin No. 1 and ground. If continuity exists, repair circuit No. 512A (No. 512 on Mark VII). If no continuity exists, go to step 10).
  10. Continuity Check Between Pressure Warning Switch & Fluid Level Sensor Unplug pressure warning sensor 5-pin connector. Using an ohmmeter, check for continuity between fluid level sensor connector pin No. 2 and ground. If continuity exists, repair circuit No. 549A (No. 549 on Mark VII). If no continuity exists, go to step 11).
  11. Pressure Warning Switch Continuity Check Using an ohmmeter, check for continuity between pressure warning switch pin No. 3 and ground, and pin No. 5 and ground. If continuity exists, replace pressure warning switch and pump/motor relay. If no continuity exists, go to step 12).
  12. Continuity Check Between Pressure Warning Switch & ECM Using an ohmmeter, check for continuity between pressure warning switch connector pin No. 5 and ground. If continuity exists, repair circuit No. 535A (No. 535 on Mark VII). If no continuity exists, plug in all connectors and reverify symptom.
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