Dodge 2001 Ram 1500 Owner's Manual page 1445

9 - 298 ENGINE 5.9L DIESEL
OIL PRESSURE RELIEF VALVE (Continued)
INSTALLATION
(1) Install the plunger, spring, and plug as shown
in (Fig. 152). Tighten the plug to 80 N·m (60 ft. lbs.)
torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pres-
sure.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3–wire, solid-state oil pressure sensor is
installed into the oil pressure galley on the engine
block. It is located below and to the rear of the
Engine Control Module (ECM) (Fig. 154).
Fig. 154 Oil Pressure Sensor (Engine) Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
OPERATION
Operation of the oil pressure sensor on the
diesel engine is controlled by the Engine Con-
trol Module (ECM). The Powertrain Control
Module (PCM) does not have any control over
the sensor.
The oil pressure sensor uses three circuits. They
are:
• A 5–volt power supply from the ECM
• A sensor ground through the ECM's sensor
return
• A signal to the ECM 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 on the gasoline powered engine.
Meaning different pressures relate to different output
voltages.
A 5–volt supply is sent to the sensor from the ECM
to power up the sensor. The sensor returns a voltage
signal back to the ECM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on the CCD bus circuit to operate
the oil pressure gauge and the check gauges lamp.
Ground for the sensor is provided by the ECM
through a low-noise sensor return.
REMOVAL
(1) Disconnect the battery negative cables.
(2) Disconnect the oil pressure sensor connector
(Fig. 155).
(3) Using a suitable socket, remove the oil pres-
sure sensor from the block (counter-clockwise).
Fig. 155 Oil Pressure Sensor Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
BR/BE