With Generic Scan Tool

Ignition Coils, Engine Code "BEL", Checking

NOTE: The ignition coil and power output stage are combined in one complete component.

Test requirement
- No malfunction regarding fuel injector(s) stored

Recognize a non-functional or misfiring cylinder as follows:
- Disconnect connectors from fuel injectors in sequence with engine running and observe engine operation.
Or
- Compare spark plugs of all cylinders to each other. Check electrodes for carbon fouling.

If faulty cylinder is recognized:
- Switch spark plug from faulty cylinder with one from another cylinder.

If malfunction follows the spark plug:
- Replace spark plug.

If malfunction remains at original cylinder:
- Switch spark plug from faulty cylinder with one from another cylinder.
- If a malfunction now occurs at other cylinder, replace the ignition coil.

If malfunction remains at the cylinder, check Ground (GND) wire of ignition coil.

Checking Ground (GND) wire of ignition coil
- Disconnect the 4-pin connector at the respective ignition coil.







- Check Ground (GND) connection from 4-pin connector socket 4 to engine Ground (GND) for open circuit and short circuit to B+.
- Repair open circuit or short circuit if necessary.

If Ground (GND) connection is OK: Check voltage supply of ignition coil

Checking voltage supply of ignition coil







- Connect multimeter to the following connector sockets for voltage measurement:
- Switch ignition on.

4-pin connector at wiring harness, socket Specified value
1 & Ground (GND) Battery voltage

Specified value: approx. battery voltage

If specified value is not obtained:
- Check wire connection from socket 1 via fuse to Motronic Engine Control Module (ECM) Power Supply Relay -J271- for continuity, repair if necessary.

If specified value is obtained.
- Check power output stage. Power Output Stages For Ignition Coils, Checking