Component Inspection

Check MAFS performance.
1. IG "OFF".
2. Connect CHA probe to terminal 3 of MAFS and CHB probe to terminal 1 of TPS connector.
3. Warm up the engine to normal operating temperature.
4. Measure signal waveform of MAFS and TPS together by stepping on and off the accelerator pedal.
  SPECIFICATION:
  
  Fig 1: TPS And MAFS Signal Waveform Graph
5. Is the measured signal waveform (Comparison response of TPS with MAFS) O.K?
  YES : --> Go to "Check ECM/PCM" as follows.
  
  NO : --> Substitute with a known - good MAFS and check for proper operation.
  
  --> If the problem is corrected, replace MAFS and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check ECM/PCM.
1. IG "OFF" and disconnect MAFS connector.
2. Connect scantool and Key "ON".
3. Select simulation function on scantool.
4. Simulate voltage at terminal 3 of MAFS signal connector.
  
  Fig 2: Scantool Display - MAF Sensor Voltage
5. Does the signal value of MAFS change according to simulation voltage?
  YES : --> Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  
  NO : --> Substitute with a known - good ECM/PCM and check for proper operation.
  
  --> If the problem is corrected, replace ECM/PCM and go to "VERIFICATION OF VEHICLE REPAIR " procedure.