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Home >> Mitsubishi >> 2002 >> Mirage LS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 1.8L >> Diagnostic Tests >> DTC P0101: Volume Air Flow Sensor Circuit Range/Performance Problem >> Diagnostic Procedure
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Diagnostic Procedure

NOTE: After repairs, verify repair by driving vehicle according to appropriate monitor drive cycle and check for DTCs. See VERIFYING REPAIRS  .
  1. Start engine and allow to idle. Ensure engine coolant temperature is 176-203°F (80-95°C). Ensure lights, engine cooling fan and all accessories are off. Place transaxle in Neutral (M/T) or Park (A/T). Using scan tool, check data list item No. 12 (VAF SENSOR). Scan tool should read 18-44 Hz or more at idle and 68-108 Hz at 2500 RPM. When engine RPM is revved, frequency should increase in relation to increase in engine speed. If scan tool value does not read as specified, go to next step. If scan tool value reads as specified, problem is intermittent. See INTERMITTENT DIAGNOSTIC TROUBLE CODES  .
  2. Install Test Harness (MB991709) between each half of VAF sensor 7-pin connector. See Figure . Start engine and allow it to idle. Measure voltage between ground and VAF sensor connector terminal No. 7 (Blue wire). Voltage should be 0-1 volt at idle and 6-9 volts at 3000 RPM. If voltage is not within specification, go to next step. If voltage is within specification, replace VAF sensor. If problem still exists after replacing VAF sensor, replace ECM (M/T) or PCM (A/T).
  3. Turn ignition off. DO NOT disconnect ECM (M/T) or PCM (A/T) connector. Turn ignition on. Measure voltage between ground and Blue wire at ECM harness connector B40 terminal No. 19 (M/T), or PCM harness connector B77 terminal No. 19 (A/T). If voltage is 6-9 volts, check for poor, loose or damaged ECM or PCM connectors. Repair as necessary. If connectors are okay, replace ECM (M/T) or PCM (A/T). If voltage is not 6-9 volts, check for open in wire between VAF sensor and ECM (M/T) or PCM (A/T), or for poor, loose or damaged VAF sensor connector. Repair connector or wiring as necessary. If connectors and wiring are okay, replace VAF sensor.
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