check oil AUDI A6 1998 C5 / 2.G AHA Engine Multiport Fuel Injection And Ignition System Workshop Manual

24-27
Evaluation of display group 32 Display group:
32


Display fields:
1-4
Possible malfunction cause
Corrective action
O2S control
learning value:
-25.0 to -10.0
%
Engine oil dilution (when part load learning value is
normal display fields 2 and 4)
- Change engine oil, or carry out extensive
road test and check again


Fuel pressure too high- Check fuel pressure regulator page 24
-
111



Fuel injector leaking- Check fuel injectors page 24
-102


Oxygen Sensor (O2S) heater malfunction- Check O2S heater page 24
-34
O2S control
learning value:
10.0 to 25.0 %
Intake air leaks ("false air") or exhaust manifold leaks
(when partial load learning value is normal display
fields 2 and 4)
- Check intake air system for leaks page 24
-126

- Check exhaust system for leaks Repair
Manual, 2.8 Liter V6 5V General, Engine,
Repair Group 26


Fuel pressure too low- Check fuel pressure regulator page 24
-
111



Oxygen Sensor (O2S) heater malfunction- Check O2S heater page 24
-34
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24-66

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

VAG1551 or VAG1552 scan tool with
VAG1551/3 adapter

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

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) page 01
-8 .
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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24-71
Evaluation of display group 2, display field 2 Display group:
2


Display field:
2
Possible malfunction cause
Corrective action
less than 1.00
ms
Smaller values can only occur while driving during
deceleration
more than 2.50
ms Shift lever in drive range (auto. transmission)
Engine is affected by additional consumers- Move shift lever into P or N
- Eliminate load (A/C, power steering, generator)

Poor idle (does not run on all cylinders)- Check and spark plugs page 28
-21
(checking
ignition coils)
- Check fuel injectors page 24
-102


Throttle valve control module -J338- faulty- Check throttle valve control module page 24
-
128

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24-107

Checking

- Remove intake air hose between MAF sensor
and intake air noise muffler.

- Remove vacuum hose from Intake Manifold
Tuning (IMT) valve -N156- (change-over valve).

- Remove 5-pin connector from ignition coils, 2-
pin connector from valve for camshaft
adjustment -N208- (bank 2) and 2-pin connector
from camshaft position sensor -G163- (bank 1).

- Disconnect wiring harness from clips on fuel
rail.

- Disconnect fuel rail from intake manifold and remove fuel lines together
with injectors.
- Remove vacuum hose from fuel pressure regulator.
- Remove harness connectors from all injectors.
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24-110

Checking for leaks

- Conduct output DTM, actuating cylinder 1
injector -N30- page 01
-51
(fuel pump must be
running).

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.

- Visually check injector for leaks.

With fuel pump running, only 1 to 2 drops can
drip in a minute (per injector).
If fuel loss is greater:

- Replace leaking injector
Installation of the injectors is in reverse order of
removal.

- Replace O-rings on all injectors and coat O-rings
lightly with clean engine oil.

Pa
ge 140 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
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yp
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