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Home >> Eagle >> 1995 >> Summit DL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - OBD-II (2.4L) >> Diagnostic Tests >> Code P0100: Air Flow Sensor (AFS) Circuit Failure

Code P0100: Air Flow Sensor (AFS) Circuit Failure

NOTE: For component terminal identification, see TERMINAL IDENTIFICATION  in this article. For wiring diagrams, see WIRING DIAGRAMS in the WIRING DIAGRAMS  section.
NOTE: Procedures are provided by manufacturer for component testing using an engine analyzer with oscilloscope capability. Refer to manufacturer's operation manual for instructions in use of oscilloscope.
  1. If using scan tool, go to step 3). Disconnect AFS connector. Install Test Harness (MB991348 ) between AFS and AFS connector. Using engine analyzer with oscilloscope capability, connect special patterns probe to AFS connector terminal No. 3 or to PCM connector terminal No. 70.
  2. Start engine. Verify that wave form high frequency and low frequency patterns are of approximately the same length (time). Verify that wave length decreases and frequency increases as engine RPM increases. If conditions are not as specified, replace AFS. If conditions are as specified, go to step 4).
  3. Warm vehicle to normal operating temperature. Ensure headlights and accessories are off. Using scan tool, read Airflow Sensor (AFS) volume (frequency) value. See AIRFLOW SENSOR VALUES  table. Frequency should increase when engine is raced. If values are not as specified, replace AFS. If values are as specified, go to next step.
    AIRFLOW SENSOR VALUES

    Application Hz @ 700 RPM Hz @ 2000 RPM
    2.4L 18-44 43-83
  4. Disconnect AFS connector and MFI relay connector. Using DVOM, check for continuity between AFS connector terminal No. 3 and MFI relay connector terminal No. 4. If continuity does not exist, repair wiring harness as necessary. If continuity exists, go to next step.
  5. Using DVOM, check for continuity between chassis ground and AFS connector terminal No. 5. If continuity does not exist, repair wiring harness as necessary. If continuity exists, go to next step.
  6. Disconnect AFS connector and PCM connector. Ground PCM connector terminal No. 19. Using DVOM, check for continuity between chassis ground and AFS connector terminal No. 7. If continuity does not exist, repair circuit as necessary. If continuity exists, go to next step.
  7. Ground PCM connector terminal No. 70. Using DVOM, check for continuity between chassis ground and AFS connector terminal No. 3. If continuity does not exist, repair circuit as necessary. If continuity exists, go to next step.
  8. Turn ignition switch to ON position. Using DVOM, check voltage between chassis ground and AFS harness connector terminal No. 3. If voltage is not 4.8-5.2 volts, replace PCM. If voltage is as specified, condition required to set trouble code is not present at this time. Go to next step.
  9. Test is complete. Intermittent problem may exist. Road test vehicle (if necessary) and attempt to duplicate conditions that caused original complaint. Recheck for codes. If no codes are displayed, go to INTERMITTENT FAULTS .
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