The oil pressure sensor operates as a switch, at a fairly low pressure
compared to normal oil pressure with the engine running. The warning
light on the instrument panel should turn on with ignition before start,
and turn off as soon as the engine is on. There is no other indication
of a failed sensor. Even a flickering oil light while driving
is an indication of dangerously low oil pressure, and imminent engine damage
if continuing to drive. Low oil pressure can be the result of low
oil level, and on some cars a seriously sludged engine, blocked oil pickup
screen, or damaged oil pump. |
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It is located on the back of the engine block,
with a single wire connecting it to the instrument panel. Leaks from
the sensor can be hard to distinguish from leaks at the oil filler tube
o-ring seals, or the valve cover. The sensor is similar to the oil
drain plug, with aluminum gasket. The same sensor was used on the C900,
NG900, 9k, and 9-3 model from 1985-2002. (click image for full view) |
Oil Pressure Sensor
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P/N: 9112459 |
Testing
The oil pressure switch is closed (low impedance to chassis ground)
with engine off, or at oil pressure below about 6 psi. It is open
(high impedance to chassis ground) with engine running, and oil pressure
above 6 psi.
A test lead with an alligator clip can be attached to the wire connector
from the LH (driver) side of the engine. The voltage should be low
(near zero) with engine off, and high (close to the battery voltage) with
engine on. |
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