AUDI A8 1997 D2 / 1.G AEB Engine Motronic MFI And Ignition System

24-55

Engine operating conditions (engine
electronics), checking


Note:
This test checks whether the Motronic Engine
Control Module (ECM) -J220- recognizes the
engine operating conditions.

Required special tools and test equipment

VAG 1551 or VAG 1552 scan tool with VAG
1551/3 adapter

Test requirements
Engine oil temperature at least 80 C (176
F)

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.
Pa
ge 71 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

Read Measurin
g Value Block
HELP
Input display 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)
Pa
ge 72 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

24-56

- Check engine operating conditions (display field
4):

Display fields

1 2 3 4
Display group 5: Engine electronics-operating conditions
Display xxx RPM xx.xx ms xxx km/h Idle
Part throt
Full throt
1)

Decel
Enrich
Indicates Engine speed
(in 40 RPM steps) Engine load Vehicle speed Operational condition
Range 0-6800 RPM 0.00-8.50 ms --- ---
Specified value 760-960 RPM 0.50-1.50 ms 0 km/h Idle: "Idle"
Throttle slightly open: "Part throt"
Throttle quickly closed: "Decel"
Quick acceleration over 3000 RPM: "Enrich"
1) Possible only while driving
Pa
ge 73 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

If displayed values are NOT OK (not as
specified):

- Check free movement of accelerator pedal and
cable.

- Check throttle valve control module Page 24
-
99
.
Pa
ge 74 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

24-57

Mass Air Flow (MAF) sensor, checking


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
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagram

Test requirements
All electrical consumers switched off (coolant
fan must not run during test).
A/C must be switched off
Fuse for MAF sensor OK
Pa
ge 75 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

24-58

Test sequence

- 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 -2- to input display group number 2, and
press -Q- button to confirm input.
Read Measuring Value Block 2 1 2 3 4

Indicated on display (1-4 = display fields)
Pa
ge 76 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

24-59

- Compare display with specified values for
engine load (display fields 2 and 4):

Display fields

1 2 3 4
Display group 2: Load measurement
Display xxx RPM xx.xx ms xx.xx ms xx.x g/s
Indicates Engine
speed
(in 40 RPM
steps) Engine load Injection
time Mass air flow
Range 0-6800 RPM 0.00-8.50 ms 0.00-25.00
ms
Specified
value 760-960
RPM 0.50-1.50 ms 1.00-3.00
ms 1.8-4.0 g/s

2520 RPM 0.80-2.00 ms 1.50-4.00
ms 7.5-12.0 g/s
--- If not as specified Page 24
-60
,
Evaluation of display group 2
--- If not as specified Page 24
-60
,
Evaluation of display group 2
If displayed values are OK (as specified):

-
Press button to advance program
sequence.
Pa
ge 77 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

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

- Switch ignition off.
Pa
ge 78 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

24-60
Evaluation of display group 2 Display
group: 2


Display field:
2
Possible cause
Corrective action
less than 0.50
ms
Smaller values can only occur while driving during
deceleration
more than 1.50
ms Shift into drive range (auto. transmission)
Engine is affected by additional consumers- Move shift lever to P or N
- Illuminate load (A/C, power steering,
generator)

Poor idle (does not run on all cylinders)- Check spark plugs
- Check fuel injectors Page 24
-87


Throttle valve control module -J338 faulty- Check throttle valve control module
Page 24
-99

Display field:
4
Possible cause
Corrective action
less than 1.8
g/s
Large amount of false air between intake air duct and
Mass Air Flow (MAF) sensor - Check intake air system for leaks (false
air) Page 24
-97

larger than 4.0
g/s
Shift lever in drive range (auto. transmission)
Engine affected by additional consumers- Move shift lever to P or N
- Eliminate load (A/C, power steering,
generator)
Pa
ge 79 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1

Open circuits in wiring 3 or 4 between MAF sensor and
ECM - Check voltage supply Page 24
-61


Open circuit in wiring 1 or 2 between MAF sensor and
ECM - Check wiring Page 24
-61
Pa
ge 80 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1