AUDI A8 1995 D2 / 1.G AEB Engine Throttle Valve Control Module And Checking

24-99


Throttle valve control module,
checking

Note:
If the throttle valve control module -J338- is
removed and installed, or replaced, adaptation of
the throttle valve control module to the Motronic
ECM is required Page 24
-119
.

Required special tools and test equipment

VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagrams
Pa
ge 1 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

24-100

Function

Idle speed stabilization is integrated in the
throttle valve control module -J338-. In the
housing opposite the throttle valve are Throttle
Position (TP) sensor -G69-, Closed Throttle
Position (CTP) switch -F60-, throttle drive -G186-
and angle sensor -1- for throttle drive -G187-.

The housing should not be opened.
The individual components cannot be replaced or
mechanically adjusted. All adjustments are
accomplished by the VAG 1551 Scan Tool (ST)
using the "Basic Setting" function 04.
If the complete throttle valve control module is
without power (i.e. disconnected), the throttle
valve assumes a mechanical closed throttle
position that results in an increased idle speed of
1200-1300 RPM (with engine at operating
temperature).
If only the Throttle Position (TP) actuator -V60- is
without power, the throttle valve also assumes a
mechanical closed throttle position (limp-home
position), but because the signal from the CTP
switch -F60- can still be recognized, a nearly
"normal" idle speed of approx. 900 RPM is
maintained with a corresponding reduction of the
ignition timing advance.
If the Engine Control Module (ECM) recognizes a
Pa
ge 2 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

malfunction in the angle sensor -1- for throttle
drive -G187-, it switches the power off for throttle
drive -G186-,and the throttle valve again
assumes the mechanical closed throttle position
(limp-home position).
Pa
ge 3 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

24-101

Throttle valve control module power
supply, checking


If voltage is NOT OK: - Disconnect 8-pin harness connector from throttle valve control module
-J338-.
- Connect multimeter US 1119 (Fluke 83 or equivalent) between harness
connector terminals using adapter cables from VW 1594 connector test
kit.
- Switch ignition on, and check voltage. Specified values:

Connector terminals 3 and 7 (Ground): 9.0-14.5 volts
Connector terminals 4 and 7 (Ground): 4.0-6.0 volts
- Switch ignition off.
- Connect VAG 1598/22 test box Page 01
-56
.

- Check wiring for open circuit between ECM/test box and 8-pin harness
connector.

Connector terminal 3 to ECM/test box socket 69
Connector terminal 4 to ECM/test box socket 62
Connector terminal 7 to ECM/test box socket 67
Specified value: max. 1.5
Pa
ge 4 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

24-102

- Check wiring for short circuit between ECM/test
box and 8-pin harness connector.


Connector terminal 7 to ECM/test box
socket 69

Connector terminal 7 to ECM/test box
socket 62

Connector terminal 4 to ECM/test box
socket 67

Specified value:

- Reconnect throttle valve control module harness
connector.
If wiring is OK:

- Replace Motronic Engine Control Module (ECM)
-J220- Page 01
-57
.

- Carry out adaptation of throttle valve control
module to ECM Page 24
-119
.

-
Check readiness code Page 01
-59
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
Pa
ge 5 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

generate new readiness code Page 01
-62
.
Pa
ge 6 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

24-103

Closed Throttle Position (CTP) switch,
checking


Note:
The Closed Throttle Position (CTP) switch -F60-
is inside the throttle valve control module -J338-.

Test conditions

Throttle valve in closed throttle position; if
necessary adjust accelerator pedal cable

Repair Manual, Fuel Supply System, Repair
Group 20


Cruise control adjustment OK
Power supply for throttle valve control
module OK; checking Page 24
-101


Checking

- Connect VAG 1551 or VAG 1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
Pa
ge 7 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input display group number XXX

Indicated on display
Pa
ge 8 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

24-104

- Press buttons -0-, -0- and -5- to input display
group number 5, and press -Q- button to confirm
input. Read Measuring Value Block 5 1 2 3 4

Indicated on display (1-4 = display fields)
- Check Closed Throttle Position (CTP) switch (display field 4):

Display fields

1 2 3 4
Display group 5: Engine electronics
Display xxx RPM xx.xx ms xxx km/h Idle
Part throt
Full throt
Decel
Enrich
Indicates Engine speed
(in 40 RPM steps) Engine Load Vehicle speed Operational condition
Range 0-6800 RPM 0.00-8.50 ms --- ---
Specified value 760-960 RPM 0.50-1.50 ms 0 km/h Throttle closed: "Idle"
Throttle slightly open: "Part throt"
Pa
ge 9 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2

--- --- --- If display is NOT OK Page 24
-105
, Continuation
Pa
ge 10 of 38 Throttle valve control module, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.2