1997 AUDI A8 AEB Engine Motronic MFI And Ignition System

24-78

- Check battery positive voltage (B+) in display
field 2.

Display fields

1 2 3 4
Display group 4: Basic engine setting
Display xxx RPM xx.xxx V
xxx.x C
xxx.x 5C
Indicates Engine speed
(in 40 RPM
steps) Battery Positive Voltage (B+) Engine coolant
temperature Intake air
temperature
Range 0-6800 RPM 0.000-16.500 V -46.5 to 141.0 -46.5 to 141.0
Specified
value 0 RPM 10.000-14.500 V --- ---

--- If not as specified Page 24
-79
, Evaluation
of display group 4
--- ---
If displayed value is OK (as specified):

-
Press button to advance program
sequence.
- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.
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24-79
Evaluation of display group 4 Display group: 4


Display field: 2
Possible cause
Corrective action
No VAG 1551 display
Fuse for ECM faulty- Replace fuse
Open circuit in wiring- Voltage supply at terminal 15 Page 24
-
80

Displayed value changes between 10.0-14.5
V
Intermittent connection - Voltage supply at terminal 30 Page 24
-
79

0.0-10.0 V
Battery
discharged/faulty Voltage regulator faulty - Check battery
- Check generator
- Check voltage regulator
14.5-16.5 V Generator faultyVoltage regulator faulty - Check generator
- Check voltage regulator

Checking voltage supply at terminal 30

- Switch ignition off.

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.
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- Connect multimeter US 1119 (Fluke 83 or
equivalent) between ECM/test box sockets 2
(Ground) and 3 (B+), using adapter cables from
VW 1594 connector test kit.

Specified value: 10-14.5 volts
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24-80
If voltage is NOT OK:

- Check wiring according to applicable wiring
diagram.

Checking voltage supply at terminal 15

- Switch ignition off.

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

- Connect multimeter between ECM/test box
sockets 1 (B+) and 2 (Ground), using adapter
cables from VW 1594 connector test kit.

- Switch ignition on, and check voltage.

Specified value: 10-14.5 volts
If voltage is NOT OK:

- Check wiring according to applicable wiring
diagram.

-
Check readiness code Page 01
-59
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
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generate new readiness code Page 01
-62
.
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24-81

Fuel pump relay and connections,
checking


The fuel pump relay is located at relay position 4 on the relay panel on the
left side under the instrument panel.
Checking function of fuel pump relay -J17-
- Remove storage shelf in left-front footwell.

- Remove fuses 28, 29 and 34 from fuse panel.
- Connect VAG 1527B LED voltage tester between Ground and one of
the two terminals for fuse 28.
- Briefly crank starter.

LED test light must light up.
Fuel pump relay must be actuated (sound and vibration)
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24-82
If the fuel pump does not respond:

- Check power supply wiring Page 24
-84
.
If the LED test light does not light up:

- Repeat test at other terminal of fuse 28.

If the LED light still does not light up:
- Check wiring for open or short circuits between fuse 28 and terminal 30
at relay position 6, using the applicable wiring diagram. Repair wiring
as necessary.

Note:
This step lets the fuel pump run without the engine running. The closed
throttle position switch must be closed during the test, or the selected fuel
injector will discharge fuel when it is actuated 5 times. - Connect VAG 1527B LED voltage tester between Ground and one of
the two terminals for fuse 29.
-
Initiate output Diagnostic Test Mode (DTM) and advance to test of
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cylinder 1 fuel injector -N30- Page 01
-42
.

LED test light must light up
Fuel pump relay must be activated
Fuel pump must run
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pair&id=AUDI.B5.FU02.24.1