100S Quattro Wagon (Canada) V6-2.8L (AAH) (1992)
Mass Air Flow Sensor: Testing and Inspection
Checking Mass Air Flow Sensor
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For functional testing of the mass air flow sensor, also see On-Board Diagnostics With Scan Tool VAG 1551, "Basic Setting" function 04.
See: Computers and Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/Basic Setting (Function 04)
Test condition.
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MAF sensor circuit breaker (S74) - OK (black holder in electronics box, passenger side footwell)
Checking positive battery voltage (B+) supply.
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Ignition switched OFF
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Disconnect harness connector from MAF sensor.
CAUTION
Wait 30 seconds after switching OFF the ignition BEFORE disconnecting the Engine Control Module (ECM) harness connector.
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Connect multimeter (Fluke 83 or equivalent) between connector terminals 2 and 3 using adapter cables from VW 1594 connector test kit.
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Switch ignition on.
Specified value: approx. 12-14 volts.
If specified value is not obtained:
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Check MAF sensor circuit breaker (S74) (black holder in electronics box, passenger side footwell).
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Check continuity between connector terminal 3 and circuit breaker according to wiring diagram.
Specified value: maximum 0.5 (ohms)
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Check continuity between terminal 2 and Ground (GND).
Specified value: maximum 0.5 (ohms)
Check wiring between ECM and MAF sensor
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Connect VAG 1598 test box with VAG 1598/11 adapter harness to engine wiring harness. Refer to VAG 1598 Pin Out Box Connecting See:
Computers and Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/Scan Tool Connecting and
Initial Checks/Connecting and Testing VAG 1598 Pin Out Box
Adapter harness for ECM is not connected.
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Check signal wire (air flow signal) for continuity between MAF sensor terminal 1 and test box socket 42.
Specified value: maximum 1 (ohm)
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Check signal wire (CO% potentiometer) for continuity between MAF sensor connector terminal 4 and test box socket 41.
Specified value: maximum 1 (ohm)
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Check ground wire for continuity between MAF sensor connector terminal 2 and test box socket 45.
Specified value: maximum 1 (ohm)
If specified values are not obtained:
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Find and eliminate open or short circuit in wiring between MAF sensor connector and ECM connector A.