Removing, installing and checking auxiliary air heater element Z35 with auxiliary air heater control unit J604 — AUDI

Removing, installing and checking
auxiliary air heater element
Z35
with
auxiliary air heater control unit
J604
Installed on vehicles with a diesel engine and vehicles with a high-voltage system (hybrid vehicles with petrol engine)
Note
Vehicles with a diesel engine and no
“auxiliary heater”
optional extra are fitted with an electric supplementary heater as supplementary air heater
Audi sales range
. Heat energy is supplied to the air after leaving the heat exchanger of the air conditioning unit in the event of a request from the air conditioner front operating and display unit,
Climatronic control unit
J255
.
Vehicles with a diesel engine and
“auxiliary heater”
optional extra are currently also fitted with an electric supplementary heater. At a later date, the electric supplementary heater is to be discontinued on vehicles with a diesel engine and an
“auxiliary heater”
and the auxiliary heater will then assume the function of a supplementary heater (conversion date not yet finalised)
Audi sales range
.
The electric supplementary heater (
Z35
) is activated by way of
J604
. The control units (
J255
and
J604
) exchange the relevant information by way of a local data bus
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode and
Current flow diagrams, Electrical fault finding and Fitting locations
.
Checking operation of
Z35
and
J604
Chapter
“
Checking electric supplementary heater
”
.
With the exception of vehicles with a high-voltage system (hybrid vehicles), vehicles with petrol engine are currently not fitted with a supplementary heater (or an
“auxiliary heater”
fitted as optional extra is not activated as supplementary heater).
Vehicles with a high-voltage system (hybrid vehicles) and petrol engine are currently also fitted with a
auxiliary air heater element
Z35
.
Vehicles with a petrol engine and vehicles with a diesel engine not fitted with an
auxiliary air heater element
Z35
have an air conditioning unit with no opening for fitting
Z35
Chapter
“
Air intake and air outlet openings
”
and
Electronic parts catalogue
.
Chapter
“
Checking electric supplementary heater
”
Removing
Move the front right seat (front passenger's seat) as far back as it will go.
Switch off ignition.
Remove right footwell vent (front passenger's side)
Chapter
“
Removing and installing passenger side footwell vent
”
.
Caution
The air conditioner will not function properly if control motors and/or the corresponding connectors are interchanged
Chapter
“
Overview of control motors of air conditioner
”
.
The control motors and connectors are identical. If these are incorrectly installed or connected, the corresponding flaps can no longer be properly matched and/or activated.
Mark control motors and connectors clearly before detaching or removing to prevent incorrect installation.
Remove air-intake box
Chapter
“
Removing and installing air intake box of front air conditioning unit
”
.
Remove the
right centre vent control motor
V111
Chapter
“
Removing and installing
right centre vent control motor
V111
”
.
Caution
Risk of short circuit when disconnecting the power supply to the
auxiliary air heater element
Z35
Remove the fuse in the power supply to the
auxiliary air heater element
Z35
.
Interrupt the power supply to the
auxiliary air heater element
Z35
by removing the corresponding fuse (currently 150 A).
Note
The fitting location of the fuse can be found in the relevant current flow diagram
Current flow diagrams, Electrical fault finding and Fitting locations
.
Unplug the connector
A
from the
supplementary air heater control unit
J604
D
.
Check again using a voltage tester. There must not be any voltage between the connections
C
(positive) and
B
(negative) (danger of short circuit).
Note
To prevent interchange of the connections
C
(positive) and
B
(negative), the diameters are different (M6 thread and M8 thread on
J604
).
If the connections (
C
and
B
) are incorrectly assigned,
J604
can no longer regulate the current and there will be a constant flow of current through
Z35
(unregulated with maximum heat output).
Detach the two wires
B
and
C
to
J604
.
After detaching, insulate the two wires
B
and
C
separately (risk of short circuit).
Remove bolts
E
.
WARNING
The
auxiliary air heater element
Z35
may be hot.
If
Z35
has been activated prior to removal, do not touch
Z35
.
Pull
J604
A
(with
Z35
B
, cannot be checked and replaced separately) out of the mounting slot
C
of the air conditioning unit.
Installing
Install in reverse order of removal; note the following:
Check the mounting slot
C
of the air conditioning unit for contamination with
Z35
B
removed and clean if necessary.
Check the partition between the left and right side in the air conditioning unit by way of the mounting slot
C
for
Z35
.
Slide
Z35
B
with
J604
A
into the mounting slot
C
of the air conditioning unit.
Only install
Z35
B
in the mounts
F
of the air conditioning unit with the rubber bushes
D
at the lugs
E
.
Fit bolts
E
.
Attach the two wires
B
and
C
to
J604
.
Tightening torque of hexagon nut (M8 thread) at connection
B
20 Nm
Tightening torque of hexagon nut (M6 thread) at connection
C
9 Nm
Re-install all components removed in reverse order.
Perform basic setting and final control diagnosis for the air conditioner
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
Note
The control motors on this vehicle are equipped with electronics. A new control motor only learns its position at the air conditioning unit in the course of basic setting and can then be activated by the air conditioner front operating and display unit,
Climatronic control unit
J255
(all control motors are identical at present)
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
While you are performing the basic setting, the control motors are assigned and adapted in accordance with the series connection of the wiring. If the sequence is not as specified, the control motors will not be adapted properly and the flaps will not be controlled correctly
Chapter
“
Overview of control motors of air conditioner
”
.
Interrogate the event memory of
J255
and erase any faults displayed
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode.
After installation, check the activation and operation of
Z35
by way of
J604
if applicable
Vehicle diagnostic tester
in
“Guided Fault Finding”
mode and
Chapter
“
Checking electric supplementary heater
”
.