sensor AUDI A4 1998 B5 / 1.G AC System On Board Diagnostic User Guide

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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4) A/C compressor speed sensor G111 is not installed on Nippondenso compressors. If A/C control head -E87- is not coded
correctly according to compressor type, A/C Clutch -N25- will only engage briefly and shut off due to no speed signal input.
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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-
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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.
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01-41

VAG1551 scan tool
display Possible cause
Corrective action
01296
Sender for Outlet
Temperature, Center -
G191-

Short circuit to ground /SP

Open circuit/short circuit to
positive /SP - Short or open circuit in wiring/connections between -
G191- and -E87-
- Sensor -G191- malfunctioning- Diagnose and repair short or open
circuit in wiring using wiring
diagram
- -G191- electrical check page
01
-115

01297
Sender for Outlet
Temperature, Floor Outlet
-G192-

Short circuit to ground /SP

Open circuit/short circuit to
positive /SP - Short or open circuit in wiring/connections between -
G192- and
-E87-.
- -G192- malfunctioning- Diagnose and repair short or open
circuit in wiring using wiring
diagram.
- -G192- electrical check page
01
-115

65535
A/C control head -E87-

Malfunction
- Short or open circuit in wiring/connections between
terminal -15- or -31- to -E87-, contact resistance or
loose connection
- -E87- malfunctioning- Diagnose and repair short or open
circuit in wiring to -E87- using wiring
diagram

- Replace A/C control head -E87-
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7 - Footwell/Defroster Flap Motor -V85-

8 - Air Flow Flap Motor -V71-

9 - Interior Temperature Sensor Fan -V42-

10 - A/C control head display segment test

11 - Outside Air Temperature Display -G106-
test

1) Not installed on m.y. 1997 vehicles.
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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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For the A/C control head -E87-, the instrument panel interior temperature sensor -G56- is installed with only one display in
the -E87-. -V42- and -G56- are not individually replaceable. If -E87- is malfunctioning, they must be replaced together.
A/C control heads with one display indicate that output diagnostic test mode is completed after activation of the last
component ("END" is indicated on the Scan Tool display).
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01-50

VAG1551 scan tool
display Specified function
Corrective action
Interior Temperature
Sensor Fan V42 - V42 (for temperature sensor in
instrument panel) is switched on and off
every 5 seconds1) - Test wiring/connections between V42 and -E87- for
open circuit or short circuit to ground using wiring
diagram
- Test voltage supply for V42 using wiring diagram
- Check intake slot and intake hose for
restriction page 87
-145

- Replace -E87-
1)Confirm operation by blowing smoke over intake slot on center of instrument panel.
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01-54

Notes:

For m.y. 1996, because A/C engine coolant
temperature sensor G110 is not installed on
USA/CDN models, during basic setting, DTC
"00799 engine coolant temperature sensor
G110" is stored and must be erased.
For m.y. 1997 A/C engine coolant temperature
(ECT) sensor -G110- is deleted, and will no
longer load a DTC when checking DTC memory
after ending basic setting.

- Check DTC memory page 01
-18
.

- Erase DTC memory (function 05) and end
output (function 06) page 01
-55
.
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