Dodge RAM 1500 1998 Owner's Manual page 1290

DR
OIL PAN (Continued)
(12) Install the front crossmember(Refer to 13 -
FRAME & BUMPERS/FRAME/FRONT
MEMBER - INSTALLATION).
(13) Fill engine oil.
(14) Reconnect the negative battery cable.
(15) Start engine and check for leaks.
Fig. 74 Oil Pan Mounting Bolt Sequence
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3 wire, solid-state engine oil pressure sensor
(sending unit) is located in an engine oil pressure
gallery.
OPERATION
The oil pressure sensor uses three circuits. They
are:
• A 5 volt power supply from the Powertrain Con-
trol Module (PCM)
• A sensor ground through the PCM's sensor
return
• A signal to the PCM relating to engine oil pres-
sure
The oil pressure sensor has a 3 wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor. Meaning different pressures
relate to different output voltages.
A 5 volt supply is sent to the sensor from the PCM
to power up the sensor. The sensor returns a voltage
signal back to the PCM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on either a CCD or PCI bus circuit
CROSS- (depending on vehicle line) to operate the oil pressure
gauge and the check gauges lamp. Ground for the
sensor is provided by the PCM through a low-noise
sensor return.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Raise vehicle on hoist.
(3) Remove front splash shield.
(4) Disconnect oil pressure sender wire (Fig. 75).
(5) Remove the pressure sender (Fig. 75).
Fig. 75 OIL PRESSURE SENDING UNIT
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
INSTALLATION
(1) Install oil pressure sender.
(2) Connect oil pressure sender wire.
(3) Install front splash shield.
(4) Lower vehicle.
(5) Connect the negative battery cable.
OIL PUMP
REMOVAL
(1) Remove the oil pan and pick-up tube (Refer to
9 - ENGINE/LUBRICATION/OIL PAN - REMOVAL).
(2) Remove the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
ENGINE - 3.7L 9 - 67