1999 AUDI A4 engine

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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24-150

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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24-153

Transmission Range (TR) signal,
checking


Notes:

Through the multi-function Transmission Range
(TR) program switch -F125- at the transmission,
the Engine Control Module (ECM) recognizes
whether a drive range is selected (selector lever
in 2/3/4/R/D) or not (selector lever in P or N)
The multi-function Transmission Range (TR)
program switch -F125- at the transmission
switches to Ground through terminal 22 of the
ECM when the shift lever is in N or P.
When a drive range is selected, the switch
opens and terminal 22 now has power.

Required special tools and test equipment
VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box

Test procedure

-
Connect VAG 1551 or VAG 1552 scan tool and
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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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24-157

Timing control during shifting, checking


Notes:

When shifting the automatic transmission, this
signal from the Transmission Control Module
(TCM) retards the ignition timing briefly,
depending on vehicle speed and engine RPM
(reduction of torque), to reduce shift pressure.
Because of the very brief signal to reduce
torque, the signal is not always recognized by
the VAG 1551 scan tool, and therefore is not
always indicated.

Required special tools and test equipment
VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
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