wheel AUDI A4 1997 B5 / 1.G AHA Engine Multiport Fuel Injection And Ignition System Workshop Manual

24-1


Motronic Multiport Fuel
Injection (MFI) and ignition
system Component locations

Data Link Connector (DLC)
Fuel pump relay
Oxygen Sensor (O2S) behind Three Way
Catalytic Converter (TWC) -G130-, with Oxygen
Sensor (O2S) heater -Z29-
Located under knee bar, left side of steering
wheel
Position 6 on relay panel in driver's side footwell
Bank 1, sensor 2
In exhaust system behind TWC
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24-2


Oxygen Sensor (O2S) 2 behind Three Way
Catalytic Converter (TWC) -G131-, with Oxygen
Sensor (O2S) heater -Z30-
EVAP system Leak Detection Pump (LDP) -
V144-
Bank 2, sensor 2
In exhaust system behind TWC
In left-rear wheelhousing behind splash shield
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24-13
Technical data

Engine code
AHA
Engine idle speed (with consumers
switched off)
not adjustable, maintained by Idle Air
Control (IAC) All-wheel drive vehicles 620-740 RPM
Front-wheel drive vehicles 740-860 RPM
Engine speed (RPM) upper limit
actuated by switching off fuel injectors approx. 6500 RPM
Fuel system pressure at idle With pressure regulator vacuum hose
connected approx. 3.2-3.8 bar
(46-55 psi)
With pressure regulator vacuum hose
disconnected approx. 3.8-4.2 bar
(55-61 psi)
Residual fuel pressure after 10 minutes Cold engine approx. 2.2 bar
(32 psi)
Warm engine approx. 3.0 bar
(44 psi)
Fuel injectors Spray pattern approx. the same for all fuel
injectors
Resistance 1)
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24-19

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

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) 80.0 - 105.0 C
(176 - 221 F) -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)

If not as specified Evaluation of
display group 1 page 24
-21

--- If not as specified:
- Check HO2S and O2S control before TWC
page 24
-22

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24-20
If displayed values are OK (as specified):

-
Press button.
- Press buttons -0- and -6- to insert "End Output"
address word 06, and press -Q- button to
confirm input.

- Check readiness code page 01
-70
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
generate new readiness code page 01
-73
.

Note:
The increased idle speed for vehicles with front-
wheel drive is achieved if there is voltage (from
terminal 15er) supplied to terminal 10 of the
Engine Control Module (ECM).
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24-21
Evaluation of display group 1 Display
Group: 1


Display
field: 1
Possible malfunction cause
Corrective action
less than
620
(all-wheel
drive)
or
less than
740
(front-wheel
drive)
Driving mode engaged
Adaptation of throttle valve control module -J338- to
engine control module cannot be conducted
Throttle valve control module malfunction- Move selector lever into "P" or "N" position
- Carry out adaptation of throttle valve control
module -J338- to ECM page 24
-150

- Check -J338- page 24
-128
less than
740
(front-wheel
drive)
B+ (15) to terminal 10 of ECM missing- Check voltage supply to terminal 10 on ECM
per wiring diagram
greater than
740
(all-wheel
drive) Adaptation of throttle valve control module -J338- to
engine control module cannot be conducted
Closed Throttle Position (CTP) switch open
Throttle valve control module malfunction- Carry out adaptation of throttle valve control
module -J338- to ECM page 24
-150

- Check -J338- page 24
-128
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or
greater than
860
(front-wheel
drive)


Intake air leaks ("false air")- Check intake air system for leaks page 24
-
126

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24-67

- Check engine operating conditions (display field
4):

Display fields

1 2 3 4
Display group 5: Engine electronics-operating conditions
Display xxx RPM xx.xx ms xxx km/h Idle
Part throt
Full throt 1)
Decel
Enrich
Indicates Engine speed
(in 40 RPM steps) Engine load Vehicle speed Operational condition
Range 0 - 6800 RPM 0.00 - 12.75 ms --- ---
Specified value 620 - 740 RPM
(all-wheel drive)
or
740 - 860 RPM
(front-wheel drive) 1.00 - 2.50 ms 0 km/h Idle: "Idle"
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24-70


Display fields

1 2 3 4
Display group 2: Load measurement
Display xxx RPM xx.xx ms xx.xx ms xx.x g/s
Indicates Engine
speed
(in 40 RPM
steps) Engine load Injection
time Mass air flow
Range 0 - 6800
RPM 0.00 - 12.75 ms 0.00 -
20.00 ms 0.0 - 140 g/s
Specified
value 620 - 740
RPM
(all-wheel
drive)
or
740 - 860
RPM
(front-wheel
drive) 1.00 - 2.50 ms 2.00 - 5.00
ms 2.8 - 5.6 g/s

2520 RPM 0.80 - 2.50 ms 1.60 - 5.00
ms 10.0 - 15.0 g/s
--- If not as specified page 24
-71
,
--- If not as specified page 24
-72
,
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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
ge 165 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
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yp
e=re
pair&id=AUDI.B5.FU03.24.1