1998 AUDI A4 heater

01-171
Test table display group 003 Display
field Display on VAG
1551 scan tool Malfunction cause
Malfunction repair
1 Greater than 750
RPM
Closed Throttle Position (CTP)
switch -F60- Large air leak quantity Idle Air Control (IAC) valve -N71-
sticks or is hard to move Rear windshield heater on Display group 04, display field 4
- Check -F60- page 24
-73
- Repair cause
- Check using output diagnostic test mode
page 01
-145

- Switch electrical consumers off
Less than 650 RPM
Idle Air Control (IAC) valve -N71-
sticks or is hard to move Closed Throttle Position (CTP)
switch -F60- Driving mode selected (automatic
transmission) Display group 004, display field 4
- Check using output diagnostic test mode
page 01
-145

- Check -F60- page 24
-73
- Move selector lever to P or N
2 Outside tolerance
range
Poor idle (not running on all
cylinders) Mass Air Flow (MAF) sensor -G70-
faulty Idle Air Control (IAC) valve -N71-
faulty Electrical consumers on- Fuel injectors or spark plugs faulty
- Check DTC memory page 01
-13
and/or
display group 001, display field 2 and 3
- Check DTC memory page 01
-13
and/or
display group 018
- Switch electrical consumers off
- Center steering wheel
Pa
ge 238 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-176

Display
field Display on VAG 1551
scan tool Malfunction cause
Malfunction repair
4 Not 001 10
Closed Throttle Position (CTP) switch -F60 activated or faulty A/C compressor switched on Rear window heating switched on Driving mode selected (automatic
transmission) - Check and adjust -F60- page 24
-
73

- Switch A/C off
- Check A/C compressor shut-off
page 24
-90

- Move selector lever to P or N
Note:
Display field 4 (shift inputs) can be used to recognize whether the components described below are recognized by the Engine
Control Module (ECM) as switched on or off. Display group 023 gives an exact description of the shift inputs. 0
0
1

1
0
Meaning of 5-digit shift inputs

1 = Shifting Signal (0 = not active / 1 = active)

2 = Gear recognition signal (always "1" except that display = "0" for automatic transmission vehicles with
gear engaged)

3 = -----------

4 = Mechanical Closed Throttle Position (CTP) switch (1 = closed / 0 = open)

5 = A/C compressor OFF/ON (0 = off, 1 = on)

6 = Rear window heater signal (always "0" except for vehicles without A/C and with rear window heater
on)
Pa
ge 247 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-191

Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
3/4 Display does not fluctuate-constant
between 0.0 - 0.3 V and/or between
0.6 - 0.9 V
Fuel injector faulty- Check fuel injectors page 24
-29

Spark plug faultyLarge intake air leak Engine Coolant Temperature
(ECT) sensor -G62- faulty EVAP canister purge
regulator valve -N80- - Check spark plug
- Repair cause
- Check DTC memory page 01
-13

and/or check -G62-
- Check using output diagnostic test
mode page 01
-145
and/or check -
N80-

Heated Oxygen Sensor
(HO2S) -G39- faulty or dirty Oxygen Sensor (O2S) heater
-Z19- does not function - Check DTC memory page 01
-13

and/or check -G39-
- Check -Z19- page 24
-49

Fuel system pressure too
high or too low - Check fuel pressure regulator and
residual pressure page 24
-20


Constant 2.550 V Short to positive (B+) through:
Heated Oxygen Sensor
(HO2S) -G39- wiring Engine Control Module
(ECM) -J192- - Check -G39- page 24
-49Pa
ge 267 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-205
Display group 023 Display shows
Display/specified value
Designation
Basic setting 23
1 2 3 4 X 1 = Upshift or downshift signal
XX 2 = Gear recognition signal and shifting signal
XX 3 = A/C compressor off/on and rear window heater signal
X 4 = A/C compressor shut-off Notes on display field 1:

The signal for upshift and downshift will only be output by the Transmission Control Module (TCM) for the automatic
transmission 01V. For vehicles without automatic transmission 01V, a "1" is always displayed.
Check upshift and downshift signal page 24
-103
.
X
Meaning of 1-digit display:

With vehicle not running:
Value "0" = Selector lever in R
Value "1" = Selector lever in 2,3,4,D,P,N

When driving-vehicle speed greater than 14 km/h (9 mph):
Value "0" = Ignition angle retarded for downshift selected
Pa
ge 289 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-207
Note on display field 3: X
X
Meaning of the 2-digit display:

1 = A/C compressor off/on (0 = off; 1 = on)
Notes:

On vehicles without A/C "0" is always displayed.
Check A/C compressor page 24
-90
.
The A/C compressor is shut off for approx. 12 sec. by -J192- when accelerating from a stop and from low speed.
If the gas pedal is released sooner, the time is reduced to a minimum of 3 sec. At wide open throttle, the A/C
compressor is switched off by the automatic transmission (kick-down switch).

2 = Rear window heating - Signal (0 = off; 1 = on)
Notes:
The rear window heating signal is only displayed on vehicles without A/C.
On vehicles with A/C "0" is always displayed.
Check rear window heater signal page 24
-88
.
Notes on display field 4:

If the A/C compressor is off display field 3; display field 4 can be used to recognize whether the compressor was
switched off by the engine control module. Meaning of the 1-digit display:
Pa
ge 292 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-213
Notes on display field 1:

All readiness code values are set to "1" by disconnecting the ECM harness connector and/or disconnecting the battery,
and every time DTC memory is erased (both with address word 01 function 05 and with address word 33 mode 4).
To regenerate the readiness code, take a drive of approx. 1-1/2 to 5 minutes at 80-100 km/h (50-63 mph) with manual
transmission in 4th or 5th gear, or automatic transmission selector lever in "D" position, preferably in 4th gear ("mixed city
and highway" trip).
Value "0" = Diagnosis carried out
Value "1" = Diagnosis not OK and/or diagnosis not carried out yet
X
X
X

X
X

X
Meaning of the 6-digit "readiness codes"

1 = Three way catalytic converter diagnosis (Banks 1 and 2)

2 = ----

3 = Evaporative Emissions (EVAP) throughput diagnosis

4 = Secondary air system throughput and leak diagnosis (Always "0" for vehicles without
secondary air injection system)

5 = ----

6 = Heated oxygen sensor diagnosis (flank rise and/or flank fall time of the voltage signal of
heated oxygen sensors in front of three way catalytic converters

7 = Oxygen sensor heating diagnosis (all four O2S heaters)

8 = Exhaust Gas Recirculation (EGR) throughput diagnosis
Pa
ge 303 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

(for diagnostic conditions display groups 007 and 008)

6 = Heated oxygen sensor diagnosis (flank rise and/or flank fall time of the voltage signal on
the heated oxygen sensor in front of three way catalytic converter; for diagnostic conditions
display group 042)
7 = Oxygen sensor heating diagnosis (all four O2S heaters)

8 = Exhaust Gas Recirculation (EGR) system throughput diagnosis
(for diagnostic conditions display group 017)
Pa
ge 305 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-241
Notes on display field 3 and 4:
Value "0" = Diagnosis condition not fulfilled
Value "1" = Diagnosis condition fulfilled X
X
X
X
X
X
X
X
Meaning of 8-digit display "Diagnosis condition 1"

1 = Coolant temperature: 70 - 110 C ( display group 001)
2 = Oxygen sensor heating (all four O2S heaters; display group 040)
3 = Momentary constant drive

4 = No fuel enrichment (during diagnosis no enrichment can occur)

5 = Long-term constant drive

6 = Closed throttle position switch open ( display group 002)
7 = Oxygen sensor control, bank 2 active ( display group 008)
8 = Oxygen sensor control, bank 1 active ( display group 007)
Pa
ge 337 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1