sensor CHRYSLER VOYAGER 1996 Service Manual

The first injector sensor is used only on the fuel
injector for the number±1 cylinder (Fig. 3). It is not
used on the injectors for cylinders number 2, 3, or 4.
FUEL INJECTOR SENSORÐGROUND
Provides a low noise ground for the fuel injector
sensor only.
ENGINE COOLANT TEMPERATURE SENSORÐPCM
INPUT
The 0±5 volt input from this sensor tells the PCM
the temperature of the engine coolant. Based on the
voltage received at the PCM, it will then determine
operation of the fuel timing solenoid, glow plug relay,
electrical vacuum modulator (emission component)
and generator (charging system).
The sensor is located on the side of the #3 cylinder
head near the rear of fuel injection pump (Fig. 4).
ENGINE SPEED SENSORÐPCM INPUT
The engine speed sensor is mounted to the trans-
mission bellhousing at the left/rear side of the engine
block (Fig. 5).
The engine speed sensor produces its own output
signal. If this signal is not received the engine will
not start by the PCM.
The engine speed sensor input is used in conjunc-
tion with the first injector sensor to establish fuel
injection pump timing.
The flywheel has four notches at its outer edge
(Fig. 6). Each notch is spaced equally every 90É. The
notches cause a pulse to be generated when they
pass under the speed sensor (Fig. 6). These pulses
are the input to the PCM. The input from this sensor
determines crankshaft position (in degrees) by moni-
toring the notches.The sensor also generates an rpm signal to the
PCM. This signal is used as an input for the Diesel
relay for control of the generator field, vehicle speed
control, and instrument panel mounted tachometer.
If the engine speed sensor should fail, the system
is unable to compensate for the problem and the car
will stop.
Fig. 3 Fuel Injector Sensor
Fig. 4 Engine Coolant Temperature Sensor Location
Fig. 5 Engine Speed Sensor Location
14 - 46 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)

AIR CONDITIONING (A/C) CONTROLSÐPCM
INPUTS
The A/C control system information applies to fac-
tory installed air conditioning units.
A/C REQUEST SIGNAL:When either the A/C or
Defrost mode has been selected and the A/C low and
high±pressure switches are closed, an input signal is
sent to the powertrain control module (PCM). The
PCM uses this input to cycle the A/C compressor
through the A/C relay.
If the A/C low or high±pressure switch opens, the
PCM will not receive an A/C request signal. The
PCM will then remove the ground from the A/C relay.
This will deactivate the A/C compressor clutch. Also,
if the engine coolant reaches a temperature outside
normal of its normal range, or it overheats, the PCM
will deactivate the A/C clutch.
BRAKE SWITCHÐPCM INPUT
When the brake light switch is activated, the PCM
receives an input indicating that the brakes are
being applied. After receiving this input, the PCM is
used to control the speed control system. There is a
Primary and a Secondary brake switch. The Second-
ary brake switch is closed until the brake pedal is
pressed.
DATA LINK CONNECTORÐPCM INPUT AND
OUTPUT
The 16±way data link connector (diagnostic scan
tool connector) links the Diagnostic Readout Box(DRB) scan tool with the PCM. The data link connec-
tor is located under the instrument panel near the
bottom of steering column (Fig. 7).
VEHICLE SPEED SENSORÐPCM INPUT
The vehicle speed sensor (Fig. 8) is located in the
extension housing of the transmission. The sensor
input is used by the PCM to determine vehicle speed
and distance traveled.
Fig. 6 Speed Sensor Operation
Fig. 7 Data Link Connector Location
Fig. 8 Vehicle Speed SensorÐTypical
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 47
DESCRIPTION AND OPERATION (Continued)

The speed sensor generates 8 pulses per sensor
revolution. These signals, in conjunction with a
closed throttle signal from the throttle position sen-
sor, indicate a closed throttle deceleration to the
PCM. When the vehicle is stopped at idle, a closed
throttle signal is received by the PCM (but a speed
sensor signal is not received).
In addition to determining distance and vehicle
speed, the output from the sensor is used to control
speed control operation.
SPEED CONTROLÐPCM INPUTS
The speed control system provides five separate
inputs to the PCM; On/Off, Set, Resume/Accel, Cancel,
and Decel.. The On/Off input informs the PCM that
the speed control system has been activated. The Set
input informs the PCM that a fixed vehicle speed has
been selected. The Resume input indicates to the PCM
that the previous fixed speed is requested.
Speed control operation will start at 50 km/h±142
km/h (35±85 mph). The upper range of operation is
not restricted by vehicle speed. Inputs that affect
speed control operation are vehicle speed sensor and
throttle position sensor.
Refer to Group 8H for further speed control infor-
mation.
DIESEL PCM RELAYÐPCM INPUT
A 12 volt signal at this input indicates to the PCM
that the Diesel relay has been activated. The Diesel
relay is located in the PDC. The PDC is located next
to the battery in the engine compartment. For the
location of the relay within the PDC, refer to label on
PDC cover.
This input is used only to sense that the Diesel
relay is energized. If the PCM does not see 12 volts +
at this input when the Diesel relay should be acti-
vated, it will set a Diagnostic Trouble Code (DTC).
FIVE VOLT POWERÐPCM OUTPUT
This circuit supplies approximately 5 volts to
power the Accelerator Pedal Postion Sensor, Mass Air
Flow Sensor, and A/C Pressure Sensor.
ENGINE COOLANT GAUGEÐPCM OUTPUT
Refer to the Instrument Panel and Gauges group
for additional information.
ENGINE OIL PRESSURE GAUGEÐPCM OUTPUT
Refer to the Instrument Panel and Gauges group
for additional information.
GLOW PLUG LAMPÐPCM OUTPUT
The Glow Plug lamp (malfunction indicator lamp)
illuminates on the message center each time the igni-
tion (key) switch is turned on. It will stay on for
about two seconds as a bulb test.If the PCM receives an incorrect signal, or no sig-
nal from certain sensors or components, the lamp
BLINKS. This is a warning that the PCM has
recorded a system or sensor malfunction. It signals
an immediate need for service. There are only 5
HARD faults that can turn on this lamp to make it
blink.
SPEED CONTROLÐPCM OUTPUTS
These two circuits control the fuel quantity actua-
tor to regulate vehicle speed. Refer to Group 8H for
Speed Control information.
AIR CONDITIONING RELAYÐPCM OUTPUT
This circuit controls a ground signal for operation
of the A/C clutch relay. Also refer to Air Conditioning
(A/C) ControlsÐPCM Input for additional informa-
tion.
The A/C relay is located in the Power Distribution
Center (PDC). The PDC is located next to the battery
in the engine compartment. For the location of the
relay within the PDC, refer to label on PDC cover.
FUEL TIMING SOLENOIDÐPCM OUTPUT
The fuel timing solenoid is located on the bottom of
the fuel injection pump (Fig. 10).
This 12+ volt, pulse width modulated (duty±cycle)
output controls the amount of fuel timing (advance)
in the fuel injection pump. The higher the duty-
Fig. 9 Glow Plug Lamp Symbol
Fig. 10 Fuel Timing Solenoid
14 - 48 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)

±cycle, the lower the advance. The lower the duty-
±cycle, the more advanced the fuel timing.
The duty±cycle is determined by the PCM from
inputs it receives from the fuel injector sensor and
engine speed sensor.
TACHOMETERÐPCM OUTPUT
The PCM supplies engine rpm values to the Body
Controller that then supplies the instrument cluster
mounted tachometer (if equipped). Refer to Group 8E
for tachometer information.
GLOW PLUG RELAYÐPCM OUTPUT
The glow plug relay is located in the engine com-
partment on the left±inner fender (Fig. 11).
When the ignition (key) switch is placed in the ON
position, a signal is sent to the PCM relating current
engine coolant temperature. This signal is sent from
the engine coolant temperature sensor.
After receiving this signal, the PCM will determine
if, when and for how long a period the glow plug
relay should be activated. This is done before, during
and after the engine is started. Whenever the glow
plug relay is activated, it will control the 12V+ 100
amp circuit for the operation of the four glow plugs.
The Glow Plug lamp is tied to this circuit. Lamp
operation is also controlled by the PCM.
With a cold engine, the glow plug relay and glow
plugs may be activated for a maximum time of 200
seconds. Refer to the following Glow Plug Control
chart for a temperature/time comparison of glow plug
relay operation.In this chart, Pre±Heat and Post±Heat times are
mentioned. Pre±heat is the amount of time the glow
plug relay circuit is activated when the ignition (key)
switch is ON, but the engine has yet to be started.
Post±heat is the amount of time the glow plug relay
circuit is activated after the engine is operating. The
Glow Plug lamp will not be illuminated during the
post±heat cycle.
GLOW PLUGS
Glow plugs are used to help start a cold or cool
engine. The plug will heat up and glow to heat the
combustion chamber of each cylinder. An individual
plug is used for each cylinder. Each plug is threaded
into the cylinder head above the fuel injector (Fig. 12).
Each plug will momentarily draw approximately 25
amps of electrical current during the initial key±on
cycle. This is on a cold or cool engine. After heating,
Fig. 11 Glow Plug Relay Location
GLOW PLUG CONTROL
Fig. 12 Glow Plug
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 49
DESCRIPTION AND OPERATION (Continued)

the current draw will drop to approximately 9±12
amps per plug.
Total momentary current draw for all four plugs is
approximately 100 amps on a cold engine dropping to
a total of approximately 40 amps after the plugs are
heated.
Electrical operation of the glow plugs are con-
trolled by the glow plug relay. Refer to the previous
Glow Plug RelayÐPCM Output for additional infor-
mation.
EXHAUST GAS RECIRCULATION (EGR)
SOLENOIDÐPCM OUTPUT
This circuit controls operation of the Exhaust Gas
Recirculation (EGR) solenoid. The EGR solenoid (Fig.
11) controls operation of the EGR valve.
Refer to Group 25, Emission Control System for
information. See EGR solenoid.
DIAGNOSIS AND TESTING
DIESEL DIAGONSTICS
The PCM controller does engine off diagonstics
tests, which may be heard for about 60 seconds after
turning the key off.
DIESEL PCM RELAY TEST
To perform a test of the relay and its related cir-
cuitry, refer to the DRB scan tool. To test the relay
only, refer to RelaysÐOperation/Testing in this sec-
tion of the group.
Diagnostic Trouble Codes:Refer to On-Board
Diagnostics in Group 25, Emission Control System
for a list of Diagnostic Trouble Codes (DTC's) for cer-
tain fuel system components.
ENGINE SPEED SENSOR TEST
To perform a test of the engine speed sensor and
its related circuitry, refer to the DRB scan tool.
Diagnostic Trouble Codes:Refer to On-Board
Diagnostics in Group 25, Emission Control System
for a list of Diagnostic Trouble Codes (DTC's) for cer-
tain fuel system components.
ENGINE COOLANT TEMPERATURE SENSOR TEST
The sensor is located on the side of cylinder head
near the rear of fuel injection pump (Fig. 13).
For a list of Diagnostic Trouble Codes (DTC's) for
certain fuel system components, refer to On-Board
Diagnostics in Group 25, Emission Control System.
To test the sensor only, refer to the following:
(1) Disconnect wire harness connector from coolant
temperature sensor.
(2) Test the resistance of the sensor with a high
input impedance (digital) volt±ohmmeter. The resis-
tance (as measured across the sensor terminals)should be less than 1340 ohms with the engine
warm. Refer to the following Sensor Resistance
(OHMS) chart. Replace the sensor if it is not within
the range of resistance specified in the chart.
(3) Test continuity of the wire harness. Do this
between the PCM wire harness connector and the
sensor connector terminal. Also test continuity of
wire harness to the sensor connector terminal. Refer
Fig. 13 Engine Coolant Temperature Sensor
Location
SENSOR RESISTANCE (OHMS)
14 - 50 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)

to Group 8W for wiring connector and circuitry infor-
mation. Repair the wire harness if an open circuit is
indicated.
(4) After tests are completed, connect electrical
connector to sensor.
GLOW PLUG TEST
Hard starting or a rough idle after starting may be
caused by one or more defective glow plugs. Before
testing the glow plugs, a test of the glow plug relay
should be performed. This will ensure that 12V+ is
available at the plugs when starting the engine.
Refer to the Glow Plug Relay Test for information.
For accurate test results, the glow plugs should be
removed from the engine. The plugs must be checked
when cold.Do not check the plugs if the engine
has recently been operated. If plugs are
checked when warm, incorrect amp gauge
readings will result.
Use Churchill Glow Plug Tester DX.900 or an
equivalent (Fig. 14) for the following tests. This
tester is equipped with 4 timer lamps.
(1) Remove the glow plugs from the engine. Refer
to Glow Plug Removal/Installation.
(2) Attach the red lead of the tester to the 12V+
(positive) side of the battery.
(3) Attach the black lead of the tester to the 12V±
(negative) side of the battery.
(4) Fit the glow plug into the top of the tester and
secure it with the spring loaded bar (Fig. 14).
(5) Attach the third lead wire of the tester to the
electrical terminal at the end of the glow plug.(6) When performing the test, the tester button
(Fig. 14) should be held continuously without release
for 20 seconds as indicated by the 4 timer lamps.
Each illuminated lamp represents a 5 second time
lapse.
(a) Press and hold the tester button (Fig. 14)
and note the amp gauge reading. The gauge read-
ing should indicate a momentary, initial current
draw (surge) of approximately 25 amps. After the
initial surge, the amp gauge reading should begin
to fall off. The glow plug tip should start to glow
an orange color after 5 seconds. If the tip did not
glow after 5 seconds, replace the glow plug. Before
discarding the glow plug, check the position of the
circuit breaker on the bottom of the plug tester. It
may have to be reset. Reset if necessary.
(b) Continue to hold the tester button while
observing the amp gauge and the 4 timer lamps.
When all 4 lamps are illuminated, indicating a 20
second time lapse, the amp gauge reading should
indicate a 9±12 amp current draw. If not, replace
the glow plug. Refer to Glow Plug Removal/Instal-
lation.
(7) Check each glow plug in this manner using one
20 second cycle. If the glow plug is to be retested, it
must first be allowed to cool to room temperature.
WARNING: THE GLOW PLUG WILL BECOME
EXTREMELY HOT (GLOWING) DURING THESE
TESTS. BURNS COULD RESULT IF IMPROPERLY
HANDLED. ALLOW THE GLOW PLUG TO COOL
BEFORE REMOVING FROM TESTER.
(8) Remove the glow plug from the tester.
GLOW PLUG RELAY TEST
The glow plug relay is located in the engine com-
partment on the left±inner fender (Fig. 15).
When the ignition (key) switch is placed in the ON
position, a signal is sent to the PCM relating current
engine coolant temperature. This signal is sent from
the engine coolant temperature sensor.
After receiving this signal, the PCM will deter-
mine if, when and for how long a period the glow
plug relay should be activated. This is done before,
during and after the engine is started. Whenever the
glow plug relay is activated, it will control the 12V+
100 amp circuit for the operation of the four glow
plugs.
The Glow Plug lamp is tied to this circuit. Lamp
operation is also controlled by the PCM.
With a cold engine, the glow plug relay and glow
plugs may be activated for a maximum time of 200
seconds. Refer to the Glow Plug Control chart for a
temperature/time comparison of glow plug relay oper-
ation.
Fig. 14 Typical Glow Plug Tester
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 51
DIAGNOSIS AND TESTING (Continued)

²When the PCM energizes the Diesel PCM and
other relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.
TESTING
The following procedure applies to the Diesel PCM
and other relays.
(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between termi-
nals 85 and 86. The resistance should be between 75
65 ohms.
(3) Connect the ohmmeter between terminals 30
and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.
(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source.Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the Die-
sel PCM and other relay circuits. Refer to group 8W,
Wiring Diagrams.
BOOST PRESSURE SENSOR
If the boost pressure sensor fails, the PCM records
a DTC into memory and continues to operate the
engine in one of the three ªlimp-inº modes. When the
PCM is operating in this mode, a loss of power will
be present, as if the turbocharger was not operating.
The best method for diagnosing faults with the boost
pressure sensor is with the DRB III scan tool.
Diagnostic Trouble Codes:Refer to On-Board
Diagnostics in Group 25, Emission Control System
for a list of Diagnostic Trouble Codes (DTC's) for cer-
tain fuel system components.
VEHICLE SPEED SENSOR TEST
To perform a test of the sensor and its related cir-
cuitry, refer to DRB scan tool.
Diagnostic Trouble Codes:Refer to On-Board
Diagnostics in Group 25, Emission Control System
for a list of Diagnostic Trouble Codes (DTC's) for cer-
tain fuel system components.
DIAGNOSTIC TROUBLE CODES
For a list of Diagnostic Trouble Codes (DTC's),
refer to Group 25, Emission Control System for infor-
mation. See On-Board Diagnostics.
REMOVAL AND INSTALLATION
DIESEL PCM RELAY
The Diesel PCM relay is located in the PDC. For
the location of the relay within the PDC, refer to
label on PDC cover.
A/C CLUTCH RELAY
The A/C clutch relay is located in the PDC. For the
location of the relay within the PDC, refer to label on
PDC cover.
ENGINE SPEED SENSOR
The engine speed sensor is mounted to the trans-
mission bellhousing at the rear of the engine block
(Fig. 18).
REMOVAL
(1) Disconnect the harness (on the sensor) from
the main electrical harness.
Fig. 17 Diesel PCM and Other Relay Terminals
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 53
DIAGNOSIS AND TESTING (Continued)

(2) Remove the sensor mounting bolts.
(3) Remove the sensor.
INSTALLATION
(1) Install the sensor flush against the opening in
the transmission housing.
(2) Install and tighten the sensor mounting bolt to
19 N´m (14 ft. lbs.) torque.
(3) Connect the electrical connector to the sensor.
ENGINE COOLANT TEMPERATURE SENSOR
The sensor is located on the side of cylinder head
near the rear of fuel injection pump (Fig. 19).
REMOVAL
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
REFER TO GROUP 7, COOLING.
(1) Partially drain cooling system. Refer to Group
7, Cooling.
(2) Disconnect electrical connector from sensor.
(3) Remove sensor from cylinder head.
INSTALLATION
(1) Install a new copper gasket to sensor.
(2) Install sensor to cylinder head.
(3) Tighten sensor to 18 N´m (13 ft. lbs.) torque.
(4) Connect electrical connector to sensor.
(5) Replace any lost engine coolant. Refer to Group
7, Cooling System.
GLOW PLUGS
The glow plugs are located above each fuel injector
(Fig. 20). Four individual plugs are used.
REMOVAL
(1) Disconnect the negative battery cable at the
battery.
(2) Clean the area around the glow plug with com-
pressed air before removal.
(3) Disconnect electrical connector (Fig. 21) at glow
plug.
(4) Remove the glow plug (Fig. 20) from cylinder
head.
Fig. 18 Engine Speed SensorFig. 19 Engine Coolant Temperature Sensor
Location
Fig. 20 Glow Plug
14 - 54 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Apply high±temperature anti±seize compound
to glow plug threads before installation
(2) Install the glow plug into the cylinder head.
Tighten to 23 N´m (203 in. lbs.) torque.
(3) Connect battery cable to battery.
GLOW PLUG RELAY
The glow plug relay is located in the engine com-
partment on the left±inner fender (Fig. 22).
REMOVAL
(1) Disconnect the negative battery cable at the
battery.
(2) Remove relay mounting bolt.(3) Disconnect electrical connector at relay and
remove relay.
INSTALLATION
(1) Check condition of electrical connector for dam-
age or corrosion. Repair as necessary.
(2) Install electrical connector to relay.
(3) Install relay to inner fender.
(4) Connect battery cable to battery.
POWERTRAIN CONTROL MODULE (PCM)
The PCM is mounted to a bracket located in the
center consule in front of the air bag module (Fig.
23).
REMOVAL
(1) Disconnect the negative battery cable at the
battery.
(2) Loosen the 68±Way connector (Fig. 23). The
electrical connector has a sliding bar which moves
inward to lock or outward to unlock.
(3) Remove the electrical connector by pulling
straight out.
(4) Remove PCM.
INSTALLATION
(1) After the PCM electrical connector has been
separated from the PCM, inspect the pins for corro-
sion, being spread apart, bent or misaligned. Also
inspect the pin heights in the connector. If the pin
heights are different, this would indicate a pin has
separated from the connector. Repair as necessary.
(2) Engage 68±way connector into PCM. Move
slide bar to lock connector.
(3) Connect negative cable to battery.
VEHICLE SPEED SENSOR
The vehicle speed sensor (Fig. 24) is located on the
extension housing of the transmission.
Fig. 21 Glow Plug Electrical Connector
Fig. 22 Glow Plug Relay Location
Fig. 23 PCM Location
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 55
REMOVAL AND INSTALLATION (Continued)

REMOVAL
(1) Raise and support vehicle.
(2) Clean the area around the sensor before
removal.
(3) Disconnect the electrical connector from the
sensor (Fig. 25).
(4) Remove the sensor mounting bolt (Fig. 25).
(5) Pull the sensor from the speedometer pinion
gear adapter for removal.
INSTALLATION
(1) Install new sensor into speedometer gear
adapter.(2) Tighten sensor mounting bolt. To prevent dam-
age to sensor or speedometer adapter, be sure the
sensor is mounted flush to the adapter before tight-
ening.
(3) Connect electrical connector to sensor.
SPECIFICATIONS
GLOW PLUG CURRENT DRAW
Initial Current Draw:Approximately 22±25
amps per plug.
After 20 seconds of operation:Approximately
9±12 amps per plug.
Fig. 25 Sensor Removal/InstallationÐTypicalFig. 24 Vehicle Speed Sensor LocationÐTypical
14 - 56 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
REMOVAL AND INSTALLATION (Continued)