Ignition Coil, Checking

Ignition Coil, 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:
- 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.


Specification: approx.: 2K Ohm.

If specification is not obtained:
- Replace spark plug connector.

If specification is obtained:
- Exchange spark plug from faulty (misfiring) cylinder with one from another cylinder. Visually check spark plug for damage e.g.: cracks on ceramic body of spark plug.
- If malfunction (misfire) occurs now on other cylinder, replace spark plug.

If the malfunction remains at the same cylinder:
- Exchange ignition coil from faulty (misfiring) cylinder with one from another cylinder. Visually check ignition coil for damage (ignition coil could be cracked or bursted)
- If malfunction occurs now on other cylinder, replace ignition coil.

If malfunction remains at the same cylinder.
- Disconnect harness connector from ignition coil.







- 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.

If the Ground (GND) connection is OK.
- 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. Specification: approx. battery voltage

If the specification is not obtained:
- Check wiring.

If the specification is obtained:
- Disconnect 3-pin harness connectors on power output stages for ignition coils; component locations overview.
- Then connect diode test lamp to 3-pin connectors for both output stages.







- Connect diode test lamp VAG1527 to following contacts on connectors for power output stages:

3-pin harness Specification (with
connector terminal starter activated)
1 + Ground Diode test lamp (GND) should
2 + Ground (GND) light up
3 + Ground (GND)

If the specifications are not obtained:
- Switch ignition off.







Check the following wiring connections for open circuits and/or short to B+ or Ground (GND).

Black 3-pin 3-pin connector
connector on on ignition coil
power output stage, terminal terminal
1 1 (cylinder 1)
2 1 (cylinder 2)
3 1 (cylinder 3)







Check the following wiring connections for open circuits and/or short to B+ or Ground (GND).

Brown 3-pin 3-pin connector on
connector on power ignition coil,
output stage, terminal terminal

1 1 (cylinder 4)
2 1 (cylinder 5)
3 1 (cylinder 6)

- Eliminate any open/short circuit as necessary.