Checking fuel temperature sender G81 — VW

Checking
fuel temperature sender
G81
Special tools and workshop equipment required
Adapter cable (68-pin)
V.A.G 1598/18A
or
adapter
V.A.G 1598/22
Hand multimeter
V.A.G 1526C
or
multimeter
V.A.G 1715
Auxiliary measuring 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 engine electronics control unit with
“address word 01”
. Engine must be idling. (Connecting fault reader and selecting engine electronics control unit
Chapter
.)
Indicated on display:
Rapid data transfer HELP
Select function XX
Press buttons
0
and
8
for function
“Read measured value block”
and confirm entry with
Q
button.
Indicated on display:
Read measured value block HELP
Input display group number XXX
Press buttons
0
,
0
and
7
for
“Display group number 7”
and confirm entry with
Q
button.
Indicated on display:
Read measured value block 7 ->
15.4°C 15.9°C 16.7°C
If no realistic display appears in display zone 1 or a substitute temperature of -5.4°C is displayed, check
fuel temperature sender
G81
and line connections to sender as follows:
Press
→
button.
Press buttons
0
and
6
for function
“End data transfer”
and confirm entry with
Q
button.
Switch off ignition.
Engine code AGD (with 68-pin control unit)
Disconnect connector for
fuel temperature sender
G81
(connector to injection pump quantity adjuster).
Measure sender resistance at connector contacts 4+7.
Engine codes AGD (with 80-pin control unit), AHG, AKU
Disconnect 10-pin connector for
fuel temperature sender
G81
(connector to injection pump quantity adjuster).
Measure sender resistance at connector contacts 4+7.
Continuation for all engine codes
Specification see diagram
Scale A shows resistance values for temperature range 0..50°C and scale B the values for temperature range 50..100°C.
Examples:
30 °C corresponds to a resistance of 1500..2000 Ω
80 °C corresponds to a resistance of 275..375 Ω
If the specification is not achieved:
Renew injection pump
Chapter
.
If the specification is attained:
Engine code AGD (with 68-pin control unit)
Connect
adapter cable, 68-pin
V.A.G 1598/18A
to control unit wiring harness.
Check lines between
adapter cable (68-pin)
V.A.G 1598/18A
and connector for open circuit according to current flow diagram. Contact 7+socket 63 Contact 4+socket 33.
Cable resistance: max. 1.5 Ω.
Engine codes AGD (with 80-pin control unit), AHG, AKU
Connect
adapter
V.A.G 1598/22
to control unit wiring harness.
Check lines between
adapter
V.A.G 1598/22
and connector for open circuit according to current flow diagram. Contact 7+socket 53 Contact 4+socket 76.
Cable resistance: max. 1.5 Ω.
Continuation for all engine codes
Also check wiring for short to one another, short to vehicle earth and short to battery positive.
Specification: ∞ Ω.
If no fault in lines is detected:
Renew
diesel direct injection system control unit
J248
Chapter
.