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

24-4


6 -
Intake Air Temperature (IAT) sensor -G42-
7 -
Harness connector
For HO2S 2 -G108- with O2S heater -Z28-4-pin connector, blackFor bank 2, sensor 1
8 -
Harness connector For Knock Sensor (KS) 2 -G66-3-pin connector, blue
9 -
Harness connector For engine speed (RPM) sensor -G28-3-pin connector, gray
10 -
Electronics box (E-box)
Contains:Motronic Engine Control Module (ECM) -
J220- Secondary Air Injection (AIR) pump relay -
J299-
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24-5


11 -
Valve 2 for camshaft adjustment -N208-
12 -
Camshaft Position (CMP) sensor -G163-,
bank 1
13 -
Heated Oxygen Sensor (HO2S) -G39- with
Oxygen Sensor (O2S) heater -Z19-
Bank 1, sensor 1
14 -
Ground (GND) connection To right engine support
15 -
Mass Air Flow (MAF) sensor -G70-
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24-6


16 -
EVAP canister purge regulator valve -N80-
17 -
Engine Coolant Temperature (ECT) sensor
-G62-
4-pin connectorIn coolant pipe behind right cylinder head
(Bank 1)
18 -
Throttle valve control module -J338-
Includes:Throttle drive -G186-Angle sensor 1 for throttle drive -G187-Throttle Position (TP) sensor -G69-Closed Throttle Position (CTP) switch -
F60-
19 -
Intake Manifold Tuning (IMT) valve -N156-
(change-over valve)
20 -
Fuel pressure regulator
Pa
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24-7


21 -
Engine speed (RPM) sensor -G28-
In transmission housing above differential
22 -
Camshaft Position (CMP) sensor -G40-,
bank 2
23 -
Heated Oxygen Sensor (HO2S) 2 -G108-
with Oxygen Sensor (O2S) heater -Z28- Bank 2, sensor 1
24 -
Knock Sensor (KS) 2 -G66-
25 -
Ignition coils and power output stage
Includes:Ignition coil -N-Ignition coil 2 -N128-Ignition coil 3 -N158-Power output stage -N122-
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24-10

WARNING!

Be alert when working on or near the engine
and ignition wires. High secondary ignition
voltage can cause serious personal injury
and damage vehicle components.

DO NOT touch or disconnect ignition system
wires when the engine is running or being
cranked at starting RPM.
DO NOT operate the starter if fuel injectors
are removed.

Be sure the ignition is switched OFF, when:
Disconnecting or connecting the battery,
ignition wires, or test equipment leads
Disconnecting fuel injection system wiring
Washing the engine or engine
compartment.

BEFORE cranking the engine at starting RPM
(e.g. for compression testing) disable ignition
and fuel injection systems:
Disconnect connector for ignition coil power
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24-11

CAUTION!

BEFORE disconnecting the battery:

Stop the engine.
Be sure the ignition is switched OFF (also
applies when connecting the battery). Failure
to do so may damage the Engine Control
Module (ECM).
Be sure of the proper radio code (for vehicles
equipped with coded anti-theft radio).

Be sure the battery negative (-) cable is
disconnected, when:
Working on the electrical system
Resistance (spot) welding or electric arc
welding anywhere on the vehicle.

When connecting and disconnecting
electrical test equipment (LED voltage tester,
multimeter, etc.):
Be sure the ignition is switched OFF.
Use correct adapters from the VW1594
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connector test kit.

For any work affecting the Engine Control
Module (ECM):
BEFORE disconnecting the ECM harness
connector, switch the ignition OFF and WAIT
at least 20 seconds. Failure to do so may
damage the ECM.
DO NOT connect any outside voltage source
to stimulate an output signal at the ECM.
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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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13.5-15.5 ohms ( )
1) Engine at room temperature; with the engine at normal operating temperature the resistance increases by approx. 4-6
ohms.
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24-14

Fuel injection system, servicing

Servicing ignition system page 28
-1

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.
Do not use any electrical contact sprays or
equivalent near oxygen sensor connections.
Pa
ge 18 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1