Component description for the oil level check switch - GF18.40-P-4114CY

WARNING: This page is about a different car, the 2011 Mercedes-Benz C300, 2010 Mercedes-Benz C300, 2009 Mercedes-Benz C300, and 2008 Mercedes-Benz C300. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 272.911 in MODEL 204.0 up to Model Year 2008

ENGINE 272.921 in MODEL 204.0/2 up to Model Year 2008

ENGINE 272.947 in MODEL 204.0/2 up to Model Year 2008

ENGINE 272.948 in MODEL 204.0 up to Model Year 2008

ENGINE 272.961 in MODEL 204.0/2 up to Model Year 2008

ENGINE 272.971 in MODEL 204.0 up to Model Year 2008

Location

Fig 1: Locating Oil Level Check Switch & Plug Connection

Courtesy of MERCEDES-BENZ USA

The switch is located inside and the connector outside on the oil pan.

Task

The switch recognizes the minimum oil level in the engine oil pan.

Body (shown with sufficient engine oil level)

Fig 2: Identifying Oil Level Check Switch Body Design

Courtesy of MERCEDES-BENZ USA

Function

The engine oil from the engine oil pan reaches the switch via 2 bore holes in the switch housing. The float is moved according to the oil level. The dry-reed contact is closed for an adequate engine oil level by the magnetic field from ring magnets. If the engine oil level becomes too low the dry-reed contact opens and the connection to the ground contact is interrupted. This is recognized by the ME-SFI [ME] control unit (N3/10) and an appropriate warning signal is sent via the chassis CAN (CAN E) to the instrument cluster (A1).

Short term fluctuations in the level are balanced out by the size of the oil volume and the 2 holes the switch housing (for example when braking or cornering) which prevents unnecessary warning signals.