fuse AUDI A6 1999 C5 / 2.G AHA Engine Multiport Fuel Injection And Ignition System Workshop Manual

output stage, and fuse for fuel pump.
Disconnect harness connectors from all fuel
injectors.
Afterward, erase Diagnostic Trouble Code
(DTC) memory.
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24-17

Test conditions

Fuses for engine electronics OK
No malfunctions stored in DTC memory
page 01
-16


Engine Coolant Temperature (ECT) at least
80 C (176 F)

All electrical consumers switched off
(radiator coolant fan must not run during
test)
A/C switched off
Exhaust system free of leaks
Automatic transmission selector lever in "P"
or "N" position
Throttle valve in Closed Throttle Position
(CTP); for Accelerator Pedal (AP) cable
adjustment Repair Manual, Fuel Supply
System, Repair Group 20
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Fuse for Oxygen Sensor (O2S) heater(s) OK
Engine Coolant Temperature (ECT) at least
80 C (176 F)
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Test requirements

Fuse for Oxygen Sensor (O2S) heater OK
Engine Coolant Temperature (ECT) at least
80 C (176 F)
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24-68

Mass Air Flow (MAF) sensor, checking


Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
VAG1598/22 test box
Multimeter US1119 (Fluke 83 or equivalent)
VW1594 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
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24-92
Evaluation of display group 4 Display group: 4


Display field: 2
Possible malfunction
cause
Corrective action
If "Control module does not answer" is
displayed
Fuse for ECM faulty- Replace fuse
Open circuit in wiring- Check voltage supply at terminal 15 page
24
-94

Displayed value changes between 10.0 -
14.5 V
Intermittent connection- Check voltage supply at terminal 15 page
24
-94

- Check voltage supply at terminal 30 page 24
-93

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
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24-95

Fuel pump relay and connections,
checking


The fuel pump relay is located at relay position 6 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 VAG1527B 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 (can be felt and heard)
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24-96
If the fuel pump does not respond:

- Check fuel pump relay actuation page 24
-
99
.
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.

Specified value: max. 1.5

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 VAG1527B LED voltage tester between Ground and one of
the two terminals for fuse 29.
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24-97
If the LED test light does not light up:

- Repeat test at other terminal of fuse 29.

If the LED test light still does not light up:
- Check wiring for open circuit between fuse 29 and terminal 30 at relay
position 6, using the applicable wiring diagram. Repair wiring as
necessary.

Specified value: max. 1.5

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 VAG1527 LED voltage tester between Ground and one of the
two terminals of fuse 34.
- Initiate output Diagnostic Test Mode (DTM) and advance to test of
cylinder 1 fuel injector -N30- page 01
-51
.

LED test light must light up
Fuel pump relay must be activated
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24-98
If the LED test light does not light up:

- Repeat test at other terminal of fuse 34.

If the LED test light still does not light up:
- Check wiring for open circuit between fuse 34 and terminal 31 at relay
position 6, using the applicable wiring diagram. Repair wiring as
necessary.

Specified value: max. 1.5
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