AUDI A4 1995 B5 / 1.G AEB Engine Motronic MFI And Ignition System

24-8
Technical data

Engine code
AEB

Engine idle speed:
not adjustable, maintained by Idle Air Control (IAC) 820-900 RPM
Engine speed (RPM) upper limit:
actuated by switching off fuel injectors approx. 6500 RPM
Fuel system pressure at idle Vacuum hose for pressure regulator connected: approx. 3.5 bar
(50 psi)

Vacuum hose for pressure regulator disconnected: approx. 4.0 bar
(58 psi)

Residual fuel pressure after 10 minutes at least 2.5 bar
Fuel injectors Spray pattern: approx. the same for all fuel injectors

Resistance
1)
:
11-13 ohm
1) Engine at room temperature; with the engine at normal operating temperature the resistance increases by approx. 4-6
ohms.
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24-9

Fuel injection system, servicing

Servicing ignition system:

Repair Group 28

Notes:

Fuel hoses in the engine compartment must be
secured with spring-type clamps. Screw-type
clamps or equivalent must not be used.
The Engine Control Module (ECM) has On
Board Diagnostic (OBD) capability, and is
equipped with Diagnostic Trouble Code (DTC)
memory. Before repairing or adjusting any
components or systems, first check DTC
memory. Also check all vacuum connections for
leaks ("false air").
For proper operation of electrical and electronic
components, a Battery Positive Voltage (B+)
supply of at least 11.5 volts is required.
Do not use any gasket sealers or other
automotive chemical compounds that contain
silicone. Traces of silicone drawn into the
engine pass unburned into the exhaust and can
damage the oxygen sensors.
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Do not use any electrical contact sprays or
equivalent near oxygen sensor connections.
Proper oxygen sensor function requires
reference to outside air via the cable. If any
contact spray reaches the oxygen sensor, it can
cause damage or improper function.
During some tests, malfunctions are recognized
by the ECM and stored in DTC memory. For
this reason, always check DTC memory after all
tests and repairs, and erase DTC memory as
necessary.
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24-10
Safety precautions Page 24
-5
Rules of cleanliness Page 24
-7
Technical data Page 24
-8
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24-11

Idle speed, checking


Notes:

Idle speed, ignition timing and CO-content
cannot be adjusted.
Idle speed is maintained by the Throttle valve
control module.
CO-content is maintained and adjusted by
Oxygen Sensor (O2S) control. Malfunctions in
O2S control are recognized by On Board
Diagnostic (OBD) and stored in DTC memory.

Required special tools and test equipment
VAG 1551 Scan Tool (ST) with VAG 1551/3
adapter cable

Test conditions
No malfunctions stored in DTC memory
Page 01
-15


Engine Coolant Temperature (ECT) at least
85 C (185 F)

All electrical consumers switched off
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(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
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24-12

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 -4- to select "Basic Setting" function 04, and
press -Q- button to confirm input.
System in Basic Settin
g
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -0- and -1- to input display group number 1, and
press -Q- button to confirm input.
System in Basic Setting 1 1 2 3 4

Indicated on display (1-4 = display fields)
Note:
After selecting function 04, the ECM initiates the following:
Continue with the test only when the operating conditions in display field 4
are satisfied.
EVAP canister purge regulator valve is closedA/C compressor is switched of
f
-
Briefly raise engine speed (acceleration burst) and let engine run at idle
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for another 2 minutes.
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24-13

- Compare display with specified values (display
fields 1-4):

Display fields

1 2 3 4
Display group 1: Engine idle speed
Display xxxx RPM
xxx.x C
xx.x% xxxxxx
Indicates Idle speed Engine Coolant
Temperature (ECT) Oxygen sensor control Adjustment
conditions
Range 0-6800 RPM
(in 40 RPM steps) --- -25.0 to 25.0 % ---
Specified
value 760-960 RPM
80.0 -105.0 C
In the range from -10.0 to 10.0 %,
the value must change by at least
2 % 111111

If not as specified Page 24
-99
,
Throttle valve control module,
checking
--- If not as specified Page 24
-99
,
Throttle valve control module,
checking
Explanation
Page 24
-15

If displayed values are OK (as specified):

- Press -C- button.

- Press buttons -0-, -5- and -6- to input display
group number 56, and press -Q- button to
confirm input.
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System in Basic Setting 56 1 2 3 4

Indicated on display (1-4 = display fields)
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yp
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pair&id=AUDI.B5.FU02.24.1