lock AUDI A6 1997 C5 / 2.G AHA Engine Multiport Fuel Injection And Ignition System User Guide

24-90

Voltage supply to Engine Control
Module (ECM), 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

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on) 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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Read Measurin
g Value Block
HELP
Input display group number XXX

Indicated on display
- Press buttons -0-, -0- and -4- to input display group number 4 (004),
and press -Q- button to confirm input.
Read Measuring Value Block 4 1 2 3 4

Indicated on display (1-4 = display fields)
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24-112

Checking

Note:
Shut-off valve of pressure tester must be open (lever parallel to direction
of flow).
Note:
For the following test, do not let the engine run unnecessarily with the
vacuum hose removed, since the higher fuel pressure causes enrichment
of the fuel air mixture. The richer mixture could exceed the O2S control
limits and therefore cause a DTC to be stored.
Note:
If, during the following pressure test, fuel leaks from the vacuum
connection of the fuel pressure regulator, replace the fuel pressure
regulator. - Connect pressure tester VAG1318 between fuel supply line and fuel
rail using adapters 1318/7, 1318/10 and 1318/13.
- Remove vacuum line from fuel pressure regulator (to intake manifold)
and block line (using VW 3093).
- Switch off all electrical consumers (rear defrost, A/C etc.).
- Start engine and let idle.
- Measure fuel pressure.
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24-117

- 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-, -7- and -0- to input display group number 70 (070),
and press -Q- button to confirm input.
Read Measuring Value Block 70 1 2 3 4

Indicated on display (1-4 = display fields)
Note:
During this diagnosis there should not be any load placed on the engine,
otherwise the diagnosis is interrupted and must be started again. - Press button -4- to select "Basic Setting" function 04 (diagnosis for
EVAP canister purge regulator valve is initiated).
System in Basic Setting 70 1 2 3 4

Indicated on display (1-4 display fields)
If the diagnosis is initiated by the ECM, the display changes from "Test
OFF" to "Test ON" in display field 4.
Note:
If the display changes from "Test ON" to "Test OFF" during the test,
accelerate with a brief burst to repeat the test. - Continue to run engine at idle until "EVAP OK" is indicated in display
field 4.
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24-118


Display fields

1 2 3 4
Display group 70: EVAP canister purge regulator valve
Display xxx % xx.x % xx.xx g/s Test OFF/Test
ON
EVAP OK
EVAP n.OK
Indicated EVAP canister purge regulator
valve duty cycle during diagnosis Oxygen sensor deviation
during diagnosis Idle Air Control (IAC) valve
deviation during diagnosis Diagnosis
condition
Diagnosis
results
Range 0 - 100 % -25.0 to +25.0 % -2.70 to +4.16 g/s ---
Specified
value 0 - 93 % - 15.0 to +15.0 % 1.00 - 0.00 g/s EVAP OK If "EVAP n.OK" is indicated in display field 4:

- Check for blockage or leaks page 24
-119
.
If "EVAP OK" is indicated in display field 4:

-
Press button.Rapid data transfer
HELP

Indicated on display
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24-119

Checking for blockage and leaks
The EVAP canister purge regulator valve is
closed when power is off.

- Remove EVAP canister purge regulator valve -
N80- (component locations page 24
-1 )

- Connect removed valve to harness connector.

- Start output Diagnostic Test Mode (DTM) and
select -N80- page 01
-51
.

- Blow into long connection during output DTM,
and check whether valve opens and closes
properly. Replace valve if necessary.
If valve -N80- does not open and close as
specified:

- Replace -N80-.
If valve -N80- is OK:

- Check all hose connections between tank and
valve for blockage or leaks.
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- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measuring Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -0- and -1- to input display group number 1 (001),
and press -Q- button to confirm input.
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24-127

Read Measuring Value Block 1 1 2 3 4

Indicated on display (1-4 = display fields)
- Monitor oxygen sensor control in display fields 3 and 4.

Display fields

1 2 3 4
Display group 1: Engine idle speed
Display xxxx RPM
xx.x C
xx.x% xx.x %
Indicates Idle speed
(in 40 RPM
steps) Engine Coolant Temperature
(ECT) Oxygen Sensor (O2S)
control, Bank 1 Oxygen Sensor (O2S)
control, Bank 2
Range 0 - 6800 RPM
-48.0 - 143.2 C
(-54 - 289 F)
-25.0 to +25.0 % -25.0 to +25.0 %
Specified
value 620 - 740
RPM
(all-wheel
drive) --- -10.0 to +10.0 %
value must change by at
least 2 % -10.0 to +10.0 %
value must change by at
least 2 %
740 - 860
RPM
(front-wheel
drive)
- Systematically spray parts of intake air system with engine leak detector spray.
Pa
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jection
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) and i
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ystem
11/23/2002 htt
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yp
e=re
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