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Home >> Mitsubishi >> 1993 >> Montero 4WD V6-2972cc 3.0L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Sensors and Switches - Computers and Control Systems >> Air Flow Meter/Sensor >> Testing and Inspection >> Oscilloscope Patterns and Waveforms
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Oscilloscope Patterns and Waveforms




Wave Pattern Inspection Using an Analyzer Measurement Method
1. Disconnect the volume air flow sensor connector, and connect the special tool (test harness: MB991348) in between. (All terminals should be connected.)
2. Connect the analyzer special patterns pickup to terminal (3) of the volume air flow sensor connector.

Note: Alternative method of connection (when test harness is not available): connect the analyzer special patterns pickup to ECM terminal (70).




Standard wave pattern
Wave pattern observation points: check that cycle time T becomes shorter and the frequency increases when the engine speed is increased.
Observation conditions: Engine idling at 700 rpm (Pattern changes with engine speed changes)

EXAMPLES OF ABNORMAL WAVE PATTERNS



Example 1
- Cause of problem: malfunction of sensor interface
- Wave pattern characteristics: rectangular wave pattern is output even when the engine is not started.




Example 2
- Cause of problem: damaged rectifier or vortex generation column
- Wave pattern characteristics: Unstable wave pattern with non-uniform frequency. However, when an ignition leak occurs during acceleration, the wave pattern will be distorted temporarily, even if the volume air flow sensor is normal.
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