Oil Level Warning System - Operation

GROUP
38

NO.
113

DATE
2/93

Oil level warning system 850

REFERENCE:
TP31875/1S(ENGLISH); 09/92; LIGHTING, INSTRUMENTS, AND OTHER ELECTRICAL COMPONENTS
TP 31427/1 (ENGLISH); 08/92; PRE-DELIVERY SERVICE INSTRUCTIONS AND PROCEDURES
TP 32127/2 (ENGLISH); 01/93; WIRING DIAGRAMS 850 1993

Oil level warning system

From approximately chassis no. 057082, 850 models are equipped with an Oil Level Warning System.

The system consists of an oil level sensor in the sump, a yellow warning lamp in the combined instrument cluster and a relay.





The sensor incorporates a float which opens a switch at low oil level, activating the relay and operating the lamp. Since the switch is normally closed, a wiring fault (e.g. open-circuit or absence of contact) will be indicated by continuous illumination of the lamp, even when the level is well above the MIN mark. The sensor is attached to the front of the sump by means of two bolts. Remove the sensor before removing the sump.

The warning lamp is yellow to indicate its reminder character.

Location of the control module is in position 201 in the central electric unit.





Before the engine is started, when the ignition key is in position 11, the lamp will be illuminated as a checking function. Also at this time, the oil level relay and the sensor monitor the oil level. After starting the engine, the lamp will light if the level is at, slightly above, or below the MIN mark on the dipstick. It will remain lit until the engine is switched off.

The oil level relay is actually a sophisticated control module incorporating electronic circuitry, a power stage and a memory.

Information regarding the previous measurement is retained in the memory. Since it takes approximately 3 minutes for oil to return from the cylinder head to the sump, this means that:

- the lamp will remain off if the car is started within 3 minutes of a measurement indicating normal level,
- the lamp will turn off if the previous measurement indicated low oil level and the next measurement recorded within a 3 minute period indicates normal oil level.

This means that the system is designed so that lamp will not illuminate when the engine is started hot and insufficient time has elapsed to permit all of the oil to return to the sump. If the car has been started from a steep slope the lamp may be on even if the oil level is normal. If this happens, drive the car to a level surface and restart the engine.

This also means that if the system has recorded low oil level and the engine is topped up, the lamp will immediately extinguish.

The oil pressure switch is connected to the relay, so if the oil pressure is low, the low level ind low pressure warning lamps light simultaneously.

Included in PDS

During transportation of the car, fuse no. 15 is removed causing the oil level warning lamp to stay illuminated when the ignition is on.

When fuse no. 15 is reinstalled, as per PDS Manual, TP 31427/1; 08/92, (or if the battery has been disconnected) the ignition must he on for approximately 4 minutes to allow the system to reset.

Note
Oil level warning lamp will be illuminated during the 4 minute reset operation.

After the 4 minute time interval, turn the ignition off, and then start the engine, to verify that the oil level warning lamp is off. This procedure is to be completed is part of the PDS, step A1.