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Home >> Mitsubishi >> 2002 >> Lancer ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0101: Volume Airflow Circuit Range/Performance Problem >> Diagnostic Procedure
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Diagnostic Procedure

  1. Start and warm engine to normal operating temperature. Using scan tool, check data list item No. 12: VOLUME AIRFLOW SENSOR. Scan tool should read 10 Hz or more at idle. When engine is raced, frequency should increase in relation to increase in engine speed. If scan tool reads as specified, problem is intermittent. See INTERMITTENT DIAGNOSTIC TROUBLE CODES  . If scan tool does not read as specified, go to next step.
  2. Turn ignition on, with engine off. Using a DVOM connected to ground, backprobe and VAF sensor harness connector terminal No. 7. VAF sensor is located on air intake pipe, near air cleaner. If voltage reading is 6-9 volts, go to step  5 . If voltage reading is not 6-9 volts, go to next step.
  3. Turn ignition off. Disconnect VAF sensor harness connector and ECM harness connector C-121 (M/T) or PCM harness connector C-120 (A/T). ECM or PCM is located under right side of dash, near glove compartment. Check for connector or terminal damage. Repair or replace as necessary. After repairs, go to step  9 . If connector and terminals are okay, go to next step.
  4. Check for short to ground in circuit between VAF sensor harness connector terminal No. 7 and ECM harness connector C-121 terminal No. 19 (M/T) or PCM harness connector C-120 terminal No. 19 (A/T). Repair as necessary. After repairs, go to step  9 . If circuit is okay, replace VAF sensor.
  5. Reconnect all disconnected harness connectors. Start and operate engine at idle. Using DVOM connected to ground, backprobe VAF sensor harness connector terminal No. 7. Voltage reading should be one volt or less with engine idling or 6-9 volts with engine speed at 3000 RPM. If voltage reading is as specified, go to step  8 . If voltage reading is not as specified, go to next step.
  6. Turn ignition off. Check for damage in VAF sensor and ECM or PCM harness connectors. Repair or replace as necessary. If harness connectors are okay, go to next step.
  7. Check for open in circuit between VAF sensor harness connector and ECM or PCM harness connector. Repair as necessary. After repairs, go to step  9 . If circuit is okay, replace ECM or PCM. After replacing ECM or PCM, go to step  9 .
  8. Replace VAF sensor. After replacing sensor, go to next step.
  9. Using scan tool, clear DTCs. Test drive vehicle following OBD-II drive cycle other monitor pattern. See OTHER MONITOR  under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Check for DTCs. If DTC P0101 is output, retry diagnostic procedure. If DTC P0101 is not output, inspection is complete.
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