engine oil AUDI A4 1998 B5 / 1.G APB Engine Ignition System Checking

without actually starting it (e.g. to test
compression), disconnect the connectors
from the output stages of the ignition coils
and from all the fuel injectors. After
completing the work, check and erase the
DTC memory.
The ignition must always be switched off
when cleaning the engine.
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Technical data, ignition system

Engine code
APB
Engine idle RPM
Not adjustable - controlled by
Idle Air Control (IAC) 750 - 850 RPM
RPM limit

Operates by closing
throttle valve
Operates by shutting off
fuel injectors
approx. 6800 RPM
Ignition timing is determined
by the control module.
Ignition timing cannot be
adjusted.
Ignition system Single-coil system with 6 ignition coils located above spark plug connectors and installed
directly on spark plugs. The power output stages are located as separate components in air
cleaner housing.
Spark plugs connectors Resistance approx.: 2K Ohm
Firing order 1-4-3-6-2-5
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Ignition coils, checking


Note:
Misfiring is recognized by the On Board
Diagnostic (OBD). This means a non working
cylinder is stored with the cylinder number in the
DTC memory. This has an advantage in case of
a malfunction the trouble shooting procedure can
be started at a certain cylinder. Check the DTC
memory of the Engine Control Module (ECM)
before commencing trouble shooting.

Test conditions

No DTCs stored relating to any of the fuel
injectors
Determine a non working or misfiring cylinder as
follows:
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- With the engine running disconnect harness
connectors in sequence from fuel injectors, and
observe the engine performance.

or

- Compare spark plugs of all cylinders with each
other and check for soot on the electrodes.
When the faulty cylinder has been identified:

- Connect hand-held multimeter (resistance
measurement) to spark plug connector:

Note:
The spark plug connector can be disconnected
from the ignition coil.

Specified value: approx.: 2K Ohm.
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If malfunction remains at the same cylinder.

- Disconnect harness connector from ignition
coil.

Electrical Wiring Diagrams, Troubleshooting & Component Locations
If the Ground (GND) connection is OK. - Check Ground (GND) connection between socket 4a and engine
Ground (GND) for open circuit and short circuit to B+. - Repair any open/short circuit as necessary.
- Connect hand-held multimeter (voltage range) to terminal 15 of
harness connector and Ground (GND).
- Disconnect harness connector from fuel injector of cylinder to be
tested.
- Operate starter.
Specified value: approx. battery voltage
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