check AUDI A6 1998 C5 / 2.G AHA Engine Motronic Ignition System Owner's Manual

28-23

Checking ignition coils -N-, -N128- and -N158-


- Disconnect 5-pin connector from ignition coil
assembly.

- Remove ignition wires from spark plugs.

If resistance is NOT OK: - Using multimeter and adapters from VAG1594 connector test kit,
measure resistance between both spark plug connectors of respective
ignition circuit (across coil).

Specification: approx. 18-25 k .- Remove ignition wires from ignition coils and measure resistance
between ends of respective ignition wires.

Specification: approx. 4.0-6.0 k
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28-24


If resistance values are not as specified:
If resistance values are OK: - Using multimeter and adapters from VAG1594 connector test kit,
measure resistance across both ignition wire connectors of respective
ignition coil.

Specification: 8.0-14.0 k - Replace coils.
- Check signal for power output stage page 28
-25
.
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28-25

Checking signal for power output stage

- Remove connectors from all 6 injectors (DTC
memory will have to be checked and erased
later).

- Switch ignition on.

If LED flashes: - Connect LED tester VAG1527 between engine ground and connector
terminal 3.
- Crank starter for several seconds.
LED in voltage tester must flash.
- Repeat test on 5-pin connector terminals 4 and 5.
- Replace ignition coils -N-, -N128- and -N158- with power output stage -
N122-.
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28-26
If LED does not flash:

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.

If wiring is OK: - Check wiring between ECM/test box and 5-pin connector for continuity
and/or short circuit per wiring diagram.

Connector terminal 3 to ECM/test box socket 71
Connector terminal 4 to ECM/test box socket 78
Connector terminal 5 to ECM/test box socket 70
- Replace Motronic ECM -J220- page 01
-68
.
- Carry out adaptation of throttle valve control module to ECM page
24
-150
.
- Check readiness code page 01
-70
.
If Diagnostic Trouble Code (DTC) memory has been erased, or ECM
has been disconnected, generate new readiness code page 01
-73
.
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28-27

Checking ground for power output stage

- Disconnect 5-pin connector from ignition coils.

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1527 LED voltage tester between B+ and terminal 2
(ground) of connector.
LED in tester must light up.
- Check wires for open circuit per wiring diagram.
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28-28

Checking voltage supply of ignition coils

Test requirement

Fuse for ignition coils OK

- Disconnect 5-pin connector from ignition coils.

- Switch ignition on.

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1527 LED voltage tester between engine ground and
terminal 1 (B+) of connector.
LED in tester must light up.
- Check wires for open circuit per wiring diagram.
- Check fuse for ignition coils.
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