Checking modulating piston travel sender G149 and quantity adjuster N146 — VW

Checking
modulating piston travel sender
G149
and
quantity adjuster
N146
The quantity adjuster is an electro-magnetic rotary positioner, which is controlled by the control unit via a targeted duty cycle. The eccentric shaft of the
quantity adjuster
N146
moves the modulating piston on the high pressure piston and thereby regulates the quantity of fuel injected.
The
modulating piston travel sender
G149
informs the control unit about the position of
quantity adjuster
N146
, thereby establishing the amount injected.
Special tools and workshop equipment required
Fault reader
V.A.G 1551
or
vehicle system tester
V.A.G 1552
with
diagnosis cable
V.A.G 1551/3
Adapter
V.A.G 1598/22
Hand multimeter
V.A.G 1526C
or
multimeter
V.A.G 1715
Adapter set
V.A.G 1594C
Current flow diagram
Test procedure
Connect
fault reader
V.A.G 1551
or
vehicle system tester
V.A.G 1552
and select control unit for engine electronics with
“address word 01”
. Engine must be idling. (Connect fault reader and select engine electronics control unit
Chapter
).
Indicated on display:
Rapid data transfer HELP
Select function XX
Press keys
0
and
8
for function
“Read measured value block”
and confirm entry with
Q
key.
Indicated on display:
Read measured value block HELP
Input display group number XXX
Press keys
0
,
0
and
1
for
“Display group number 1”
and confirm entry with
Q
key.
Indicated on display:
Read measured value block 1 ->
840 rpm 6.5 mg/H 1.480 V 87.3 °C
Check value for coolant temperature in display zone 4.
Specification: at least 85 °C
Do not continue with check until coolant temperature has been reached.
Check display in display zone 3 (voltage from
modulating piston travel sender
G149
).
Specification:
Engine code AGR 1.45…1.85 V
Engine code ALH 1.45…2.00 V
Engine code AHF 1.45…1.95 V
Engine code AGP 1.40…1.90 V
Engine code AQM 1.60…2.10 V
Read measured value block 1 ->
840 rpm 6.5 mg/H 1.480 V 87.3 °C
If specification is not attained, check
modulating piston travel sender
G149
and
metering adjuster
N146
as follows: