Ignition System: Service Precautions

Notes on avoiding damage to ignition system

In order to avoid damage to the control module, connect and disconnect the two connectors on the control module only when the ignition is switched off.

Terminal 1 of ignition coils must not be short-circuited at ground, e.g. as security alarm systems.

Install only original components of ignition system.

Do not operate ignition system at starting speed when ignition lines are not completely connected

No tests such as holding ignition cable 4 at a distance to ground, unplugging a spark plug connector or pulling cable 4 out of the ignition coils, may be performed at starting speed or when the engine is running.

Each high voltage circuit must be loaded with at least 2 k (spark plug connector).

If it is necessary to test the ignition spark when providing roadside assistance, this must only be carried out with a spark plug at a cylinder ignition cable. Ensure that the spark plug has good contact to ground.

Before working at starting speed, e.g. check compression pressure, switch off ignition and unplug connector "2" at control module.

Engine 120 has two fuel injection and ignition systems.

Use of test equipment

Connect and disconnect secondary measuring sensor to corresponding ignition lines only when engine is stopped and ignition is switched off.

If the short-circuit protection is operated (cylinder comparison) and the engine stops, it is not possible to conduct the test with this test instrument.

Do not connect a test lamp to circuits 1 and 15 of the ignition coils.