1995 AUDI A8 display

24-146

Checking

- Connect VAG 1551 or VAG 1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -5- and -0- to input display group number 50, and
press -Q- button to confirm input.
Read Measuring Value Block 50 1 2 3 4

Indicated on display (1-4 = display fields)
- Switch on A/C (lowest temperature and highest fan position).
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24-147

- Compare display with specified value in display
field 4.

Display fields

1 2 3
4
Display group 50: Signals to Engine Control Module (ECM)
Display xxxx RPM xxxx RPM A/C-LOW
Compr. ON
Compr. OFF
Indicates Actual engine
speed
(in 10 RPM steps) Specified engine
speed
(in 10 RPM steps) A/C
status A/C compressor status
Range 0-2550 RPM ---
---
Specified
value 820-900 RPM 860 RPM A/C-LOW
Compressor on: Compr. On
Compressor off: Compr. OFF

--- --- ---
If not as specified Page 24
-148
,
Continuation

Notes:

The A/C compressor is switched off during
acceleration when the car is stationary or at
slow speed.

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24-148

Continuation
If the displayed values are NOT OK:

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

- Check wiring for open circuit, short circuit to B+
or short circuit to Ground between ECM/test box
terminal 8 and A/C control head -E87-, or
Transmission Control Module (TCM).

Electrical Wiring Diagrams, Troubleshooting &
Component Locations If the wiring is OK:

- Check function of A/C control head -E87-.

Repair Manual, Heating & Air Conditioning,
Repair Group 01

Or:

Repair Manual, 5 Spd. Automatic
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24-150

Test procedure

- Connect VAG 1551 or VAG 1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -0- and -5- to input display group number 5, and
press -Q- button to confirm input.
Read Measuring Value Block 5 1 2 3 4

Indicated on display (1-4 = display fields)
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24-151

- Road test and compare indicated vehicle speed
with value in display field 3 (2nd technician
required).

Display fields

1 2 3 4
Display group 5: Engine Electronics
Display xxx RPM xx.xx ms xxx kph Idle
Part throt
Full throt
Decel
Enrich
Indicates Engine speed
(in 40 RPM
steps) Engine
load Vehicle speed Operating
condition
Range 0-6800 RPM --- --- ---
Specified
value --- --- Approx. vehicle speed ---

--- --- If no vehicle speed is displayed Page 24
-152
,
Continuation
---
If displayed value is OK:
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press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
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24-154

Read Measurin
g Value Block
HELP
Input display group number XXX

Indicated on display
- Press buttons -0-, -5- and -6- to input display group number 56, and
press -Q- button to confirm input.
Read Measuring Value Block 56 1 2 3 4

Indicated on display (1-4 = display fields)
- Compare display with specified value in display field 4:

Display fields

1 2 3
4
Display group 56: Engine idle
Display xxxx RPM xxxx RPM x.xx g/s
xxxx
Indicates Actual engine
speed
(in 10 RPM
steps) Specified engine
speed
(in 10 RPM
steps) Control value-Idle mass air flow
(idle air control valve) Operating condition
Range 0-2550 RPM --- ---
---
Specified
value 0 RPM 0 RPM -1.11 to 1.11 g/s
0000 = Selector lever in P or N
0010 = Selector lever in 2/3/4/R/D

--- --- ---
If not as specified Page 24
-155
,
Continuation;
Explanation of display Page 24-
16

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24-155
If displayed value is OK (as specified):

-
Press button toadvance program sequence.
- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

- Check readiness code Page 01
-59
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
generate new readiness code Page 01
-62
.

Continuation:
If displayed value is NOT OK (not as specified):

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

- Connect VAG 1527B LED voltage tester
between ECM/test box sockets 3 (battery
voltage, terminal 30) and 22.


LED must come on with selector lever in P
or N

LED must then go out when selecting
2/3/4/R/D
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