ignition AUDI A4 1995 B5 / 1.G AFC Engine Auxiliary Input Signals Checking Workshop Manual

24-89
If display value does not change:

- Switch ignition OFF and connect VAG 1598/19
test box to ECM harness connector page 01
-
255
.

- Connect VAG 1527B voltage tester between
VAG 1598/19 test box socket C14 and Ground
(GND).

- Switch ignition ON.

- Switch ON rear window defroster.

Voltage tester must light up
If voltage tester does not light up:

If wiring is OK:
If rear window defroster is OK: - Check wiring for continuity between C14 and rear window defroster
using wiring diagram.
- Check rear window defroster using wiring diagram.
- Replace ECM page 01
-265
.
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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:

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24-98
If no vehicle speed is displayed between
standstill and moving:

- Switch ignition OFF and connect VAG 1598/19
test box page 01
-255
.

- Connect VAG 1527B voltage tester between test
box sockets 13C (signal) and 10D (B+).

- Raise front of vehicle until left-front wheel is free
to rotate.

Note:
The right front wheel must NOT rotate.

- Switch ignition ON.

Voltage tester must light up at half strength

- Rotate left front wheel by hand.
Voltage tester must become brighter (flash)
If tester does not light up (become brighter) or
flash:

-
Check wiring between test box socket 13X and
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24-99

Transmission Range (TR) selector lever
position signal, checking


Note:
The Engine Control Module (ECM) uses this
signal to recognize the transmission range
selector lever position. When a driving mode is
selected, idle speed should drop by approx. 50
RPM to reduce creep.

Checking requirement

Control module coding OK page 01
-247
.

- Switch ignition ON.

- Using VAG 1551 scan tool, select "Read
Measuring Value Block" function 08, display
group 004, display field 4 page 01
-249
.
Read measuring value block 4 1 2 3 4

Indicated on display
CAUTION! Specified value: XXX_1X (TR selector lever in P or N)
- Apply brake and select drive mode (1, 2, 3, R or D).
Specified value: XXX_0X
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24-101

Shift procedure, checking


Notes:

The Engine Control Module (ECM) uses this
signal to briefly retard the ignition during shifting
to reduce the mechanical jerking felt between
shifts.
The shift signal is monitored by the
Transmission Control Module (TCM).

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

Carry out the following check only if a shift-
related DTC is stored in the TCM DTC memory.

Checking requirement

Control module coding OK page 01
-247


CAUTION!

Always use a second technician to operate
the VAG 1551 scan tool while driving.

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24-106

- Switch ignition ON.

- Using VAG 1551 scan tool, select "Read
Measuring Value Block" function 08, display
group 027, display field 1 page 01
-249
.
Read measuring value block 27 1 2 3 4

Indicated on display; note display field 1
If the specified value is not obtained, even though coding is OK: Specified value: 0
- Start engine and let idle.
Specified value: 1
-
Press button.- Select "End Output" function 06.
- Press -Q- button to confirm input.
- Connect VAG 1598/19 test box to ECM harness connector page 01
-
255
.
- Check wiring for open or short circuit between ECM and TCM, using
wiring diagram.
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24-108

- Switch ignition ON.

- Using VAG 1551 scan tool, select "Read
Measuring Value Block" function 08, display
group 027, display field 2 page 01
-249
.
Read measuring value block 27 1 2 3 4

Indicated on display; note display field 2
If the specified value is not obtained, even though coding is OK: Specified value: 0
- Start engine and let idle.
Specified value: 1
-
Press button.- Select "End Output" function 06.
- Press -Q- button to confirm input.
- Connect VAG 1598/19 test box to ECM harness connector page 01
-
255
.
- Check wiring for open or short circuit between ECM and instrument
cluster, using wiring diagram.
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Control module coding OK page 01
-247
.

Checking

- Switch ignition OFF.

- Connect VAG 1598/19 test box to ECM harness
connector page 01
-255
.

- Check signal wire for open or short circuit
between ECM and ABS control module, using
wiring diagram.
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