Checking pressure signal at high-pressure sender G65 — AUDI

Checking pressure signal at
high-pressure sender
G65
Note
The cooling output cannot be checked if the plug
A
is disconnected or the
G65
B
is removed; the
front air conditioner operating and display unit
E87
does not switch on the air conditioner compressor
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
To check measured values of
G65
, refer to
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
G65
exchanges information via a data bus with
E87
(in this case via the
onboard supply control unit
J519
).
Only
G65
that exchange information with
E87
via the data bus may be installed on this vehicle
Electronic parts catalogue
.
A
G65
that emits square-wave signals must not be installed on this vehicle (it may have the same design, but the part number is different)
Electronic parts catalogue
.
After the air conditioner compressor is switched off, it might take a relatively long period on this vehicle before the pressure in the high-pressure side drops. The expansion valve(s) is/are
“cold”
and the pressure on the low-pressure end increases rapidly after switch-off, the expansion valve(s) close(s) and the refrigerant can only flow slowly to the low-pressure end.
Preparation
Switch off ignition.
Remove bumper cover (front)
General body repairs, exterior
Rep. gr.
63
Bumper (front); Removing and installing bumper cover
.
Remove bolts
A
and remove air duct
B
to left condenser
Rep. gr.
19
Radiator/radiator fan; Exploded view - radiator/radiator fan
.
Unplug electrical connector
A
.
Assignment of 3-pin connector at
G65
A
Current flow diagrams, Electrical fault finding and Fitting locations
Earth
Signal output – via the local data bus to
E87
(in this case via the
onboard supply control unit
J519
)
Terminal
“75”
(positive)
Test sequence:
Switch on ignition.
Check earth and positive connection to connector
A
Current flow diagrams, Electrical fault finding and Fitting locations
.
Check connection and operation of
G65
as described in Guided Fault Finding routine
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
Note
When the electrical connector
A
is unplugged, the air conditioner compressor (
air conditioner compressor regulating valve
N280
) is not activated.
G65
is an electronic control unit which exchanges information via a data bus with
E87
(in this case via the
onboard supply control unit
J519
)
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
Re-install removed components in reverse order.
Interrogate the event memory of
E87
and erase any faults displayed
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
As a final step, check operation of heater and air conditioner.