Jetta GL L4-1.9L DSL Turbo (ALH) (2001)
Air Flow Meter/Sensor: Testing and Inspection
With Manufacturer's Scan Tool
Mass Air Flow (MAF) Sensor, Checking
The MAF sensor signal is used by the ECM to calculate the quantity injected and to control the required exhaust gas recirculation. The smaller the signal
from MAF sensor the smaller the quantity of fuel injected.
NOTE: Only gold-plated contacts must be used to repair the terminals in the connector for the MAF sensor.
Special tools and equipment
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V.A.G 1551/1552 Scan tool with adapter cable V.A.G 1551/3
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Test box VAG 1598/22 (through my 1999)
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Test box VAG 1598/31 (from my 2000)
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Digital multimeter US1119 (Fluke 83 or equivalent)
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Adapter set VAG 1594
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Wiring diagram
Requirements
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Fuse 34 must be OK
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The battery voltage must be at least 11.5 V
Test sequence
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Connect VAG 1551/1552 (Connecting scan tool and selecting engine electronics control module.), See: Testing and Inspection
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Run engine at idle speed and press buttons -0- and -1- to select "Engine electronics" address word 01.
WARNING!: Secure Scan Tool to rear seat and operate from this position (second technician required).
Indicated on display
Rapid data transfer
HELP
Select function XX
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Press buttons -0- and -8- to select "Read measured value block" and confirm entry with -Q- button.
Indicated on display
Read measured value block
HELP
Input display group number XXX
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Press buttons -0-, -1- and -0- to select "Display group number 10" and confirm entry with -Q- button.
Read measured value block 10
->
309 mg/H
1027 mbar
1011 mbar
0.0 %