Notes on avoiding damage to the ignition system - AH15.10-U-0002-01A

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Engine 104, 111, 112, 113, 119, 120

To avoid damage to the control module, the two connectors at the control module must not be disconnected or connected unless the ignition is switched off.
Do not connect a test lamp to terminals 1 and 15 of the ignition coils.
Do not short terminal 1 of the ignition coils to ground, e.g. as an anti-theft protection.
Install only genuine components of the ignition system.
Do not operate the ignition system at starting speed unless all the ignition cables are connected.
Do not perform any tests, e.g. holding ignition cable 4 close to ground, unplugging a spark plug connector or disconnecting cable 4 from the ignition coils, at cranking speed or when the engine is running.
The load (resistance) applied to any of the high voltage circuits must be at least 2 kΩ (spark plug connector).
The load (resistance) applied to the ignition coil during separate ignition coil test must not be greater than 28 kV in order to avoid damage to the ignition coil.
If the short circuit protection (cylinder comparison) is operated and the engine quits, then it is not possible to perform this particular test with this test equipment.
If it is necessary to test the ignition spark when providing roadside assistance, this test must only be performed with a spark plug attached to a cylinder ignition cable. Ensure the spark plug has a good ground contact.
Before performing any work at cranking speed, e.g. checking compression, switch off ignition and:
On HFM-SFI/ME gasoline injection and ignition system, disconnect connector "2" on control module.

On LH-SFI injection systems disconnect crankshaft position sensor connector(s) on DI control module.

Engine 120 has two DI ignition control modules.
On the LH-SFI injection systems the DI ignition control module is installed at the wheel well liner with heat conducting paste in order to ensure better heat dissipation. When replacing/installing the control module, do not remove the protective sheet; this does not impair heat dissipation.