Glow Plug: Description and Operation

AH15.20-P-0001-01A Notes for ceramic glow plugs
In order to prevent damage to the engine, it is important to observe the following information concerning ceramic glow plugs:
^ Ceramic glow plugs are very sensitive to impact shocks. Impact shocks cause invisible damage (hairline cracks) to the ceramic glow pin and lead to engine damage.
^ It is not possible to check the ceramic glow pin for mechanical damage (e.g. hairline cracks).
^ Only use ceramic glow plugs if the packaging is original and unopened.
^ If the ceramic glow plugs have been dropped, it is essential that they be replaced.
^ Only check glow plug with Diagnosis Assistance System (DAS).
^ The glow plug must not be energized with 12 volts otherwise it can be destroyed.