Beetle L4-1.9L DSL Turbo (ALH) (1998)
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Mass Air Flow Sensor: Testing and Inspection
With Manufacturer's Scan Tool
Mass Air Flow (MAF) Sensor -G70-, Checking
ECM uses MAF Sensor -G70- signal to calculate injection quantity and for regulating EGR. The smaller the -G70- signal; the smaller the quantity of
injected fuel.
Special tools
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VAG 1551/1552 Scan Tool using VAG 1551/3 Adapter cable
-
VAG 1598/22 Test Box (MY 1999)
-
VAG 1598/31 Test Box (from MY 2000)
-
Fluke 83 multimeter
-
VW 1594 Adapter kit
-
Wiring diagram
WARNING!
For safe operation, use a second technician to operate test equipment and take readings from back seat, during test drive.
Test sequence
-
Connect VAG 1551/1552 Scan Tool and start engine and let idle.
-
Press 0 and 1 buttons to select Address word 01: "Engine electronics"
Display will appear as shown (example only)
038906018M 1.9l R4 EDC 00AG 1813
->
Coding 0001
WSC XXXXX
-
Press -> button.
Display will appear as shown
Rapid data transfer
HELP
Select function XX
-
Press 0 and 8 buttons to select Function 08: "Read measuring value block".
-
Press Q button to enter input.
Display will appear as shown
Read measuring value block
HELP
Input Display group number XXX
-
Press 0,1 and 0 buttons to select "Display group 10".
-
Observe display in Display zone 1.
Specified Value: 200 to 450 mg/H
Read measuring value block 10 ->
309 mg/H 1027 mbar 1011 mbar 0.0 %
If specification not obtained
-
Check Exhaust Gas Recirculation system
If specification obtained
-
Accelerate vehicle in 3rd gear from about 1500 rpm under Wide Open Throttle.
-
Press PRINT button on VAG 1551 at approx. 3000 rpm.
-
Specification in Display zone 4:100 % (Throttle position)
Read measuring value block 10 ->
830 mg/H 1027 mbar 1850 mbar 100 %
If specification not obtained
-
Repeat test and accelerate vehicle under Wide Open Throttle.
Specification in Display zone 1: above 800 mg/H
