1997 AUDI A4 AFC Engine Auxiliary Input Signals Checking Workshop Manual

Pa
ge 9 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

24-93
If X1X_XX is displayed:

- Briefly press accelerator pedal to apply wide
open throttle.

Display must switch briefly to X0X_XX, then
X1X_XX must appear again after several
seconds.
If display does not change as described:

- Check whether A/C compressor was shut off
while accelerator pedal was being pressed.

- Check A/C system or automatic transmission.

Repair Manual, Heating & Air Conditioning,
Repair Group 01; connect VAG 1551 scan tool and select "Check DTC Memory" function 02


Repair Manual, 5 Spd. Automatic
Transmission 01V, Repair Group 01
; connect
VAG 1551 scan tool and select "Check DTC
Memory" function 02
If the display does not change as described:
Pa
ge 10 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

- Replace ECM page 01
-265
.
Pa
ge 11 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

24-94

Engine speed (RPM) signal, checking


Notes:
The RPM signal is routed from the ECM to
various electronic systems (e.g. automatic
transmission, ABS, etc.). The RPM signal is
monitored by the different electronic systems.
Carry out the following check only if the
tachometer (in the instrument cluster) is
inoperative, or if the A/C compressor is not
running.

- Connect VAG 1367 engine-tester to tachometer
using wiring diagram.

- Connect VAG 1367 engine-tester signal wire
(green terminal) to instrument cluster RPM
terminal and A/C control module RPM terminal
(connector remains connected).

- Start engine and let idle.

RPM must be displayed again
If the specified value is obtained, the malfunction
is in instrument cluster or on A/C control module.
If the RPM is not displayed on VAG 1367 engine-
Pa
ge 12 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

tester:

- Check wiring between ECM terminal C10 and
instrument cluster or A/C control module using
wiring diagram.
If wiring is OK:

- Replace ECM page 01
-265
.
Pa
ge 13 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

24-95

Fuel consumption signal, checking


Notes:

The consumption signal is internally calculated
by the ECM using "injection time."
The consumption signal is routed to both the
trip computer and the Transmission Control
Module (TCM).
The consumption signal is monitored by the
TCM

Repair Manual, 5 Spd. Automatic
Transmission 01V, Repair Group 01; On Board Diagnostic

Carry out the following check only if DTC
memory contains a stored DTC for the TCM
related to the consumption signal, or a missing or
false consumption signal, determined during the
trip computer check.

- Remove instrument cluster or TCM.

Repair Manual, Electrical Equipment, Repair
Pa
ge 14 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

Group 90; Instrument cluster, repairing


Repair Manual, 5 Spd. Automatic
Transmission 01V, Repair Group 01, On Board Diagnostic


- Connect VAG 1598 test box to instrument
cluster harness connector (I/P insert not
connected) or to TCM harness connector (TCM
not connected).

Repair Manual, Electrical Equipment, Repair
Group 90; Instrument cluster, repairing


Repair Manual, 5 Spd. Automatic
Transmission 01V; Repair Group 01, On Board Diagnostic

Pa
ge 15 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25

24-96

- Switch Fluke 83 multimeter to voltage
measurement range and connect between
signal wire (trip computer 20-pin connector) and
Ground (GND), using wiring diagram.

- Start engine and let idle.

Specified value: approx. 0.3 to 0.6 volts,
corresponding to engine speed (RPM)

- Vary engine speed continuously from 1000 to
4000 RPM.

Specified value: approx. 0.3 to 0.6 volts,
corresponding to engine speed (RPM)
If the specified value is not obtained, even
though the trip computer shows no consumption
value or there is a stored malfunction in the
TCM:

- Stop engine (switch ignition off).

- Replace trip computer and/or TCM as
required.
If the specified value is not obtained:

Pa
ge 16 of 37 Auxiliar
y in
put si
gnals, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.25