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Checking modulating piston movement sender G149 > < Checking fuel temperature sender G81

Polo Mk3

Checking modulating piston movement senderG149 and metering adjusterN146
Checking modulating piston movement sender -G149- and metering adjuster -N146-
The metering adjuster -N146- is an electromagnetic swivelling positioner which is actuated by the control unit via a specific duty cycle. The eccentric shaft on the metering adjuster -N146- moves the modulating piston on the high-pressure piston and thereby determines the quantity of fuel injected.
The modulating piston movement sender -G149- informs the control unit of the position of the quantity adjuster -N146- and therefore stipulates the amount injected.
Special tools and workshop equipment required
t  Hand multimeter -V.A.G 1526C- or multimeter -V.A.G 1715-
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with diagnosis cable -V.A.G 1551/3-
t  Adapter set -V.A.G 1594C-
t  Adapter cable, 121-pin -V.A.G 1598/31-
t  Current flow diagram
Test procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select engine electronics control unit with “address word 01”. Engine must be idling. (Connecting fault reader -V.A.G 1551- and selecting engine electronics control unit → Chapter).
   
Indicated on display:
–  Press keys 0 and 8 for function “Read measured value block” and confirm entry with Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 0 and 1 for “Display group number 1” and confirm entry with Q key.
  
Read measured value block                     
Input display group number XXX
Indicated on display:
–  Check coolant temperature in display zone 4. Specification: At least 85°C
Continue with check only if coolant temperature is achieved.
  
Read measured value block 1          ->
880 rpm   6.5 mg/stroke    1.680 V    87.3°C
–  Check voltage of modulating piston movement sender -G149- in display zone 3.
Engine code AGD
Specification: 1.400…1.800 V
Engine code AKU
Specification: 1.500…2.100 V
Continuation for all engine codes
–  Press → key.
–  Press keys 0 and 6 for function “End output” and confirm entry with Q key.
–  Switch off ignition.
–  If specification is not achieved, check modulating piston movement sender -G149- and metering adjuster -N146- as described in following:
  
Read measured value block 1                 ->
880 rpm   6.5 mg/stroke    1.680 V    87.3°C

Checking modulating piston movement sender G149 > < Checking fuel temperature sender G81