engine AUDI A4 2000 B5 / 1.G AC System On Board Diagnostic User Guide

01-21

Notes:

1997 If A/C control head -E87- is unable to
determine the duration of time when ignition is
off ("standing time"), DTC 01206 "signal for time
span ignition off" is loaded into memory. The
A/C control head will then default to a standing
time greater than 4 hours. The actual measured
values of the outside temperature sensor are
then used as instantaneous outside and engine
temperature inputs for A/C system control.
When the "heating" mode is selected under
these conditions, fresh air blower -V2- has a
delayed start (even when the actual standing
time is less than 4 hours and the engine is
warm) page 01
-86
, Read Measuring Value
Block. The outside air temperature display -
G106- may also indicate incorrect outside
temperature values.

If both display fields of the A/C control head do
not light with ignition switched on check control
head coding Page 01
-57
.
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01-24

VAG1551 scan tool
display Possible cause
Corrective action
00000
No DTC recognized If "no DTC recognized appears after performing repairs, OBD is ended.
00529 2122
Speed information
missing /SP1) - Open circuit in wiring between Engine Control Module
(ECM), instrument cluster and A/C control head -E87-
- ECM and instrument cluster supply an unusable engine
speed signal - Diagnose and repair open circuit in
wiring using wiring diagram
- Read measuring value block
page 01
-63

- Test engine speed signal
Repair Manual, Fuel Injection &
Ignition, Repair Group 24
00532 2234
Supply voltage

Signal too low /SP - Voltage drops in electrical system to levels of less than
9.5 V2)
- Contact resistance in cable connection to A/C
Refrigerant Low Pressure Switch -F73- - Test Generator (GEN) and Voltage
Regulator (VR)
Repair Manual, Engine
Mechanical, Repair Group 27
- Diagnose and repair contact
resistance using wiring diagram
1)This fault may be generated during Output Diagnostic Test Mode (DTM) (no engine speed signal recognized although A/C
compressor speed detected).
2) If voltage at -E87-connector -C3- drops below 9.5 V, compressor switches off for a minimum of 25 seconds. Compressor
switches on again when voltage exceeds 10.8 V.
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01-29

VAG1551 scan tool display
Possible cause
Corrective action
00797 3241
Sunlight Photo Sensor G107

Open circuit/short circuit to positive /SP

Short circuit to ground /SP - Short circuit or open
circuit
between -G107- and -
E87-
- Connections to -
G107-
interchanged
- -G107- malfunction- Diagnose and repair short circuit or open circuit in
wiring using wiring diagram
- Confirm connection using wiring diagram

- Test G107 using function 08
(Read measuring value block) page 01
-63
- Replace -G107-
00799 3243
A/C Engine Coolant Temperature (ECT)
Sensor G1101)

Open circuit/short circuit to positive /SP

Short circuit to ground /SP - Short circuit or open
circuit
between -G110-1) and
-E87-
- -G110-1) malfunction- Diagnose and repair short circuit or open circuit in
wiring using wiring diagram
- Test -G110-1) using function 08
(Read measuring value block)
page 01
-63

1) Not on USA/CDN models.
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01-33

VAG1551 scan
tool display Possible cause
Corrective action
01270 4121
A/C Clutch N251)

Open circuit /SP












Continued on next
page - Short circuit or open circuit in wiring between A/C
compressor speed sensor -G111-2/3) and -E87-

- Open circuit in wiring between A/C Clutch Relay J44 and
N25
- Open circuit in voltage supply or in wiring/connections
between A/C clutch relay J44 and -E87-
- J44 malfunction
- N25 malfunction
- Malfunction in refrigerant circuit (A/C Compressor Speed
Sensor G111 not producing signals or compressor siezed2/3) - Diagnose and repair short or open
circuit in wiring using wiring diagram
- -G111- electrical test page 01
-
115

- Diagnose and repair open circuit
using
wiring diagram
- Diagnose and repair open circuit
using wiring diagram

- Replace -J44-
- Repair or replace -N25- page 87
-
85

- Replace -G111- page 87
-63
- Replace compressor page 87
-38
1)During m.y. 1996, Nippondenso type A/C compressors were installed as a running change. These compressors are not
equipped with A/C speed sensor G111. DTC at A/C Clutch -N25- are only detected only on compressors equipped with A/C
Compressor speed sensor G111.
2)Sender G111 produces 4 pulses for each compressor revolution.
3)A/C Clutch is switched on for a few seconds after engine starts.
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01-34

DTC 01270 continued
VAG1551 scan
tool display Possible cause
Corrective action
01270 4121
A/C Clutch N251)

Speed difference
too great /SP3)












Continued on
next page. - Ribbed belt loose, slipping



- A/C control head -E87- not coded correctly
- Loose terminal or contact resistance in circuit between
-N25- and A/C clutch relay -J44- or in wiring/connections
between -G111-2)4) and -E87-
- N25 slipping
- Incorrect crankshaft vibration damper (diameter)
- Malfunction in refrigerant circuit (compressor not
operating freely). - Check belt tension Repair Manual,
Engine Mechanical, Repair Group 13
Compare speeds of engine and compressor
using function 08 (Read measuring value
block) page 01
-63

- Code A/C control head -E87- according to
compressor type installed4) "Zexel" or
"Nippondenso" page 01
-57

- Diagnose and repair circuit using wiring
diagram and perform electrical tests
page 01
-115

- -G111-, -J44- electrical test page 01
-
115

- Repair or replace -N25- page 87
-85
- Check for proper vibration damper part
number
- Check compressor for free operation and
replace if necessary page 87
-38

1/2) Continued from page 01
-33

3) If speed difference is 30 % to 60 %, A/C Clutch is switched on again by -E87- for not more than 9 times during a driving
period (ignition off). If speed difference is greater than 60 %, A/C Clutch remains off until engine is started again.
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01-38
Diagnostic Trouble Code (DTC) table, changes specific to vehicles 1997

Notes:
The following DTCs are no longer recognized beginning m.y. 1997:

00529 Speed info missing (sensor -G111- deleted).
00799 A/C engine coolant temperature (ECT) sensor -G110- (sensor deleted).
00801 A/C refrigerant high pressure switch -F118- (switch deleted).
01270 A/C clutch -N25- (Sensor -G111- deleted).
The following DTCs are new for 1997, or are current DTCs with additional references to 1997 changes. DTCs and component
references include various malfuction causes in the display below the DTC, etc.
VAG1551 scan tool display
Possible cause
Corrective action
00604
Back Pressure Flap Motor
Position Sensor -G113- in Air
Flow Flap Motor -V71-1)

Short circuit to ground /SP
Open circuit/short circuit to
positive /SP - Short circuit, open circuit in wiring or incorrect
terminal assignment (wires interchanged) of
connectors between -G113- and -E87-
- Air flow flap not operating freely
- -G113- in -V71- inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of air flow
flap3)
- Replace -V71-
Pa
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01-40

VAG1551 scan tool
display Possible cause
Corrective action
01206
Signal for time span
ignition off1)

implausible
signal /SP - Short or open circuit in wiring/connections
between instrument cluster and -E87-
- Instrument cluster malfunctioning.- Diagnose and repair short or open circuit in
wiring using wiring diagram.
- Check signal from instrument cluster using
function 08, Read measuring value block
page 01
-86
.
01274 4131
Air Flow Flap Motor -
V71- 2)

blocked or no
current /SP - Short or open circuit in wiring/connections
between -V71- and -E87-.
- Air flap or fresh/recirculated air flap
binding/sticking
- -V71- malfunctioning.- Diagnose and repair short or open circuit in
wiring using wiring diagram.
- Check air flap or fresh/recirculated air flap for
ease of movement.
- Check -V71- using function 03, Output
Diagnostic Test Mode (DTM) page 01
-42
.
1) If A/C control head -E87- is unable to determine the duration of time when ignition is off ("standing time"), DTC 01206
"signal for time span ignition off" is loaded into memory. The A/C control head will then default to a standing time greater than
4 hours. The actual measured values of the outside temperature sensor are then used as instantaneous outside and engine
temperature inputs for A/C system control. When the "heating" mode is selected under these conditions, the fresh air blower -
V2- has a delayed start (even when the actual standing time is less than 4 hours and the engine is warm) page 01
-86
,
Read measuring value block. The outside air temperature display -G106- may also indicate incorrect outside temperature
values.
2) -V71- operates the air flow flap as well as the fresh/recirculated air flap.
Pa
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01-43
Notes:

During Output DTM on vehicles with Control Head (E87) Part Number 8D0 820 043 D, A/C Compressor Clutch (N25) DTC
"01270, mechanical malfunction SP" may be stored even though no malfunction is present. Corrective action: When
output DTM is complete, check DTC memory. If above DTC is present, erase DTC memory.
When starting Output DTM, temperature and air distribution flap flap motors move to pre-determined positions in
preparation for individual tests: Temperature Regulator Flap Motor V68: moves to "heat" position. Central Air Flap Motor -
V70- moves to "floor & defroster outlet" position. Footwell Defroster Flap Motor V85 moves to "defrost" position.
Output DTM can be repeated several times, if necessary.
During Output DTM, vehicle must not be moved and engine speed must be less than 3000 rpm.
During Output DTM, A/C system control is switched off and all segments in both A/C control head displays are actuated.
Interior temperature sensor fan -V42- is activated via an A/C control head:
with one display after activation of the coolant fan.
with two displays after activation of air flow flap motor.
Outside air temperature display -G106- is activated via an A/C control head
with one display after activation of air flow flap motor.
with two displays after activation of idle regulation.
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01-44

Starting output Diagnostic Test Mode (DTM)

- Start engine, switch on compressor (press
"Auto" button), adjust air flow to center
instrument panel outlets only.

- Connect Scan Tool VAG1551 or 1552 in
operating mode -1-, enter address word 08 "A/C
Heating Electronics" and move forward in
program until "select function XX" appears in the
display.

- Switch on printer by pressing the PRINT button
(indicator lamp in button comes on).

- Check DTC memory page 01
-18
.

- Note any stored DTCs for reference and move
forward in program until "select function XX"
appears in the display. Rapid data transfer
HELP
Select function XX

Indicated on display (function selection)
- Press buttons -0- and -3-.
Rapid data transfer
Q
03 - Output Dia
gnostic Test Mode

Indicated on display
- Press -Q- button to confirm input.
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01-45

Notes:

If a DTM component fails to respond as
specified, perform all corrective actions, checks
and tests recommended in output DTM table
page 01
-46
.

A/C system component locations: engine
compartment page 87
-96
(note specific
model year information).

A/C system component locations: passenger
compartment page 87
-106
(note specific
model year information).

Output DTM can be ended by pressing the -C-
button.
After ending output DTM, check DTC memory
page 01
-18
.

If the readout "function unknown or cannot be
carried out at the moment" appears in the
display at the start of output DTM, e.g. when
engine not running, press button and once
again select "function 03 Output Diagnosis Test
Mode (DTM)" (DTM component "A/C Clutch
N25" is no longer actuated for this test).
Pa
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