1993 DODGE TRUCK sensor

14
- 46
FUEL
SYSTEM

Fig.
12
Rubber
L-Shaped
Fitting—MAP
Sensor-to-
Throttie
Body

Fig.
13
Engine
Coolant
Temperature
Sensor—
Typical
EXHAUST
~~

PIPE
J9214-5

Fig.
14
Single
Oxygen
Sensor
Location-3.9U5.2L/ 5.9L LDC
Engine

(23) Inspect for pinched or leaking fuel tubes. In­
spect for pinched, cracked or leaking fuel hoses. •

Fig.
15
Dual
Oxygen
Sensor
Location—5.9L HDC
Engine
(24) Inspect for exhaust system restrictions such as
pinched exhaust pipes, collapsed muffler or plugged catalytic convertor.
(25) If equipped with automatic transmission, ver­
ify that electrical harness is firmly connected to
park/neutral switch. Refer to Automatic Transmis­ sion section of Group 21.
(26) Verify that the harness connector is firmly
connected to the vehicle speed sensor (Fig. 16).

Fig.
16 Vehicle
Speed
Sensor—
Typical

(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel. (30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and clean. Inspect for chaffed wires or wires rubbing up against other components.

CAV

WIRE

COLOR DESCRIPTION
CAV
WIRE

COLOR DESCRIPTION

1 DG/RD*
MAP SENSOR 37
BK/OR OVERDRIVE LAMP
2 TN/BK*
ENGINE COOLANT TEMPERATURE SENSOR 38 PK/BK INJECTOR DRIVE
#5

3 RD/WT DIRECT BATTERY 39 GY/RD IAC MOTOR
#4

4
BK/LB*

SENSOR RETURN 40 BR/WT
IAC MOTOR
#2

5 BK/WT SIGNAL GROUND 41
BK/DG* OXYGEN SENSOR SIGNAL
6 VT/WT
5-VOLT
OUTPUT
(MAP AND TPS)
42
7 OR

8-VOLT
OUTPUT (DISTRIBUTOR PICK-UP) 43

GY/LB*
TACHOMETER SIGNAL OUTPUT (VEHICLES W/TACHOMETER)
8 44 GY CAMSHAFT POSITION SENSE
9 DB
J2-IGNITION FEED 45
LG SCI RECIEVE
10 R/WT OVERDRIVE OVERRIDE
46 CCD
(-)

11 BK/TN POWER GROUND 47 WT/OR* SPEED SENSOR SIGNAL
12 BK/TN POWER GROUND 48 BR/RD* SPEED CONTROL
SET
SWITCH
13 LB/BR
INJECTOR DRIVER
#4
49
YL/RD* SPEED CONTROL ON/OFF SWITCH
14 YL/WT
INJECTOR DRIVER
#3
50 WT/LG* SPEED CONTROL RESUME SWITCH
15 TN INJECTOR DRIVER
#2
51 DB/YL*
AUTO SHUTDOWN
(ASD)
RELAY
-
RETURN
16
WT/DB*

INJECTOR DRIVER
#1
52 PK/BK
EVAP CANISTER PURGE SOLENOID
17 DB/TN INJECTOR DRIVER
#7
(V-8
ONLY) 53 LG/RD* SPEED CONTROL VENT SOLENOID
18 DB/GY
INJECTOR DRIVER
#8
(V-8
ONLY) 54
OR/BK* SHIFT INDICATOR LIGHT (MANUAL TRANSMISSION ONLY)
19 BK/GY*
IGNITION COIL DRIVER 54
OR/BK* CONVERTOR CLUTCH SOLENOID (AUTO TRANSMISSION)
20 DG
GENERATOR FIELD CONTROL 55
OR/WT OVERDRIVE SOLENOID (AUTO TRANSMISSION ONLY)
21 BK/RD
CHARGE TEMPERATURE SENSOR 56
GY/PK SRI LAMP
(5.9L HDC
ENGINE)
22
OR/DB*

THROTTLE POSITION SENSOR
(TPS)
57
DG/OR ASD SENSE
23 TN/WT
OXYGEN SENSOR SIGNAL
(5.9L HDC
ENGINE) 58 LG/BK
INJECTOR DRIVER
#6

24 GY/BK IGNITION (CAMSHAFT POSITION SENSOR) 59
VT/BK IAC MOTOR
#1

25 PK
,
SCI
TRANSMIT 60
YL/BK* IAC MOTOR
#3

26 CCD
(-:-)
WIRE COLOR CODES LB
LIGHT BLUE
VT VIOLET

27 BR
A/C SWITCH SENSE BK BLACK
LG LIGHT GREEN
WT

WHITE
28 VT A/C SELECT BR BROWN
OR ORANGE
YL YELLOW
29 WT/PK* BRAKE SWITCH
-
DB DARK BLUE PK
PINK *
WITH TRACER
30 BY/YL*
PARK/NEUTRAL SWITCH DG DARK GREEN
RD
RED
31 GY
GRAY TN TAN
32 BK/PK*
MALFUNCTION INDICATOR LAMP
33 TN/RD*
SPEED CONTROL VACUUM SOLENOID CONNECTOR
34 DB/OR* A/C CLUTCH RELAY TERMINAL

|(pcKX>coooop0ffoj'
oooooooooojj
35 GY/YL*
EGR SOLENOID SHOWN W'41
30
50«M#5l31
604

%\
oooooooooo ••ooooooooooj

36 J9314-171
Fig.
17 PCM
Connector—Gas
Powered
Engines

•

THROTTLE

POSITION
SENSOR
CO

Fig. 18 System Schematic—3.9L (V-6) Engine
CO

14-52
FUEL
SYSTEM

•
CAMSHAFT
POSITION
SENSOR
TESTING

Refer to Group 8D, Ignition Systems for testing.

COOLANT
TEMPERATURE
SENSOR
TEST
To perform a complete test of the engine coolant
temperature sensor and its circuitry, refer to DRB II
tester and appropriate Powertrain Diagnostics Proce­
dures manual. To test the sensor only, refer to the
following: (1) Disconnect wire harness connector from coolant
temperature sensor (Fig. 21). Engines with air conditioning; When removing
the connector from sensor, do not pull directly on
wiring harness. Fabricate an L-shaped hook tool
from a coat hanger (approximately eight inches
long).
Place the hook part of tool under the connector
for removal. The connector is snapped onto the sen­ sor. It is not equipped with a lock type tab.
Fig.
21
Engine
Coolant
Temperature

Sensor—
Typical
(2) Test the resistance of the sensor with a high in­
put 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 Coolant Temperature sensor/ Charge Air Temperature sensor resistance chart. Re­
place the sensor if it is not within the range of resistance specified in the chart.
(3) Test continuity of the wire harness. Do this be­
tween the powertrain control module (PCM) wire
harness connector terminal 2 and the sensor connec­
tor terminal. Also test continuity of wire harness ter­
minal 4 to the sensor connector terminal. Repair the
wire harness if an open circuit is indicated.
(4) After tests are completed, connect electrical
connector to sensor. The sensor connector is symmet­
rical (not indexed). It can be installed to the sensor in either direction. SENSOR RESISTANCE (OHMS)-COOLANT
TEMPERATURE SENSOR/CHARGE AIR TEMPERATURE SENSOR

TEMPERATURE
RESISTANCE
(OHMS)

C F
MIN MAX
-40 -40 291,490 381,710
-20 -4 85,850 108,390
-10 14 49,250 61,430
0 32 29,330 35,990
10 50 17,990 21,810
20 68 11,370 13,610
25 77 9,120 10,880
30 86 7,370 8,750
40 104 4,900 5,750
50 122 3,330 3,880
60 140 2,310 2,670
70 158 1,630 1,870
80 176 1,170 1,340
90 194 860 970
100 212 640 720
no 230 480 540
120 248 370 410

J928D-4

CHARGE
AIR
TEMPERATURE SENSOR TEST
To perform a complete test of the intake manifold
charge air temperature sensor and its circuitry, refer
to DRB II tester and appropriate Powertrain Diag­ nostics Procedures manual. To test the sensor only,
refer to the following: (1) Disconnect the wire harness connector from the
charge air temperature sensor (Fig. 22).
Fig.
22
Charge
Air
Temperature
Sensor—Typical
(2) Test the resistance of the sensor with an input
impedance (digital) volt-ohmmeter. The resistance (as measured across the sensor terminals) should be
less than 1340 ohms with the engine warm. Refer to
the Coolant Temperature sensor/Charge Air Temper-

•

FUEL
SYSTEM
14-53 ature sensor resistance chart. Replace the sensor if it
is not within the range of resistance specified in the chart. (3) Test the resistance of the wire harness. Do this
between the powertrain control module (PCM) wire
harness connector terminal 21 and the sensor connec­ tor terminal. Also check between terminal 4 to the sensor connector terminal. Repair the wire harness
as necessary if the resistance is greater than 1 ohm.

MANIFOLD
ABSOLUTE
PRESSURE
(MAP)
SENSOR

TEST
To perform a complete test of MAP sensor (Fig. 23)
and its circuitry, refer to DRB II tester and appropri­
ate Powertrain Diagnostics Procedures manual. To
test the MAP sensor only, refer to the following: (1) Inspect the rubber L-shaped fitting from the
MAP sensor to the throttle body (Fig. 24). Repair as necessary.
MANIFOLD
ABSOLUTE

Fig.
23 Manifold
Absolute
Pressure
(MAP)
Sensor—
Typical
CAUTION:
When testing the MAP
sensor,
be
sure

that
the
harness
wires are not
damaged
by the test
meter
probes.

(2) Test the MAP sensor output voltage at the
MAP sensor connector between terminals A and B (Fig. 25). With the ignition switch ON and the en­
gine OFF, output voltage should be 4-to-5 volts. The
voltage should drop to
1.5-to-2.1
volts with a hot,
neutral idle speed condition.
(3) Test powertrain control module (PCM) pin-1 for
the same voltage described above to verify the wire
harness condition. Repair as necessary.
Fig.
24
Rubber
L-Shaped
Fitting—MAP
Sensor-to-

Throttle
Body

A.
Ground
B.
Output Voltage

C.
5
Volts
J8914-91

Fig.
25 MAP
Sensor
Connector
Terminals—Typical
(4)
Test MAP sensor supply voltage at sensor con­
nector between terminals A and C (Fig. 25) with the ignition ON. The voltage should be approximately 5
volts (±0.5V). Five volts (±0.5V) should also be at
terminal 6 of the powertrain control module (PCM)
wire harness connector. Repair or replace the wire
harness as necessary.
(5) Test the MAP sensor ground circuit at sensor
connector terminal A (Fig. 25) and PCM connector
terminal/pin-4. Repair the wire harness if necessary.
(6) Test the MAP sensor ground circuit at the
PCM connector between terminal/pin-4 and terminal/
pin-11 with an ohmmeter. If the ohmmeter indicates an open circuit, inspect for a defective sensor ground
connection. Refer to Group 8W, Wiring Diagrams for
location of this connection. If the ground connection

14-54 FUEL SYSTEM

• is good, replace the PCM. If terminal/pin-4 has a
short circuit to 12 volts +, correct this condition be­
fore replacing the PCM.

CRANKSHAFT POSITION SENSOR TEST
To perform a complete test of this sensor (Fig. 26)
and its circuitry, refer to the DRB II tester and ap­
propriate Powertrain Diagnostics Procedures manual.
To test the sensor only, refer to the following: (1) Near the rear of the right cylinder head, dis­
connect the sensor pigtail harness connector from the
main wiring harness.

Fig.
26 Crankshaft Position
Sensor—
Typical
(2) Place an ohmmeter across terminals B and C
(Fig. 27). Ohmmeter should be set to lK-to-lOK scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi­
cated.

VIEW
LOOKING
INTO

CPS
WIRING
CONNECTOR
Fig.
27
Sensor
Wiring
Connector

THROTTLE POSITION SENSOR (TPS) TEST
To perform a complete test of the TPS and its cir­
cuitry, refer to the DRB II tester and appropriate Powertrain Diagnostics Procedures manual. To test
the TPS only, refer to the following:
The TPS can be tested with a digital voltmeter.
The center terminal of the TPS is the output termi­ nal (Fig. 28).

AAANIFOLD
ABSOLUTE
Fig.
28
Throttle
Position
Sensor
(TPS)
Connector—
Typical

With the ignition key in the ON position, check the
TPS output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at wide open throttle (WOT). At idle, TPS output
voltage should must be greater than 200 millivolts.
At wide open throttle, TPS output voltage must be
less than 4.8 volts. The output voltage should in­
crease gradually as the throttle plate is slowly
opened from idle to WOT.

OXYGEN
(02)
SENSOR HEATING ELEMENT TEST
To perform a complete test of single or dual 02 sen-
sor(s) and circuitry, refer to DRB II tester and appro­
priate Powertrain Diagnostics Procedures manual. To
test the 02 sensor only, refer to the following:
On 3.9L/5.2L/5.9L LDC engines, the single 02 sen­
sor is located on the right exhaust down pipe (Fig.

29).
On 5.9L HDC engines, the dual 02 sensors are
located on each (left and right) exhaust down pipe (Fig. 29).
The 02 heating element can be tested with an ohm­
meter as follows: Disconnect the 02 sensor connector. Connect the
ohmmeter test leads across the white wire terminals
of the sensor connector. Resistance should be be­
tween 5 and 7 ohms. Replace the sensor if the ohm­ meter displays an infinity (open) reading.

•

FUEL
SYSTEM
14 - 55

Fig.
30
Dual
Oxygen
Sensors—5.9L
HDC
Engine
IDLE
AIR
CONTROL
(IAC)
MOTOR
TEST

To perform a complete test of IAC motor (Fig. 81)
and its circuitry, refer to DRB II scan tool and appro­
priate Powertrain Diagnostics Procedures manual. To
test the IAC motor only, special IAC motor exerciser tool number 7558 (Fig. 32) may be used.

CAUTION:
Proper safety precautions must be
taken

when
testing
the IAC
motor,

• Set the parking brake and block the drive wheels
• Route all tester cables away from the cooling fans,
drive belt, pulleys and exhaust components
• Provide proper ventilation while operating the en­
gine
• Always return the engine idle speed to normal be­
fore disconnecting the exerciser tool
(1) With the ignition OFF, disconnect the IAC mo­
tor wire connector at throttle body (Fig. 31).
(2) Plug the exerciser tool (7558) harness connector
into the IAC motor (Fig. 32).
MANIFOLD
ABSOLUTE
Fig.
31 IAC Motor—Typical
Fig.
32 IAC Motor
Testing—
Typical

(3) Connect the red clip of exerciser tool (7558) to
battery positive terminal. Connect the black clip to
negative battery terminal. The red light on the exer­
ciser tool will be illuminated when the exerciser is
properly connected to battery. (4) Start engine.
When the switch is in the HIGH or LOW position,
the light on the exerciser tool will flash. This indi­ cates that voltage pulses are being sent to the IAC
stepper motor.

•

FUEL SYSTEM
14 - 59
fill
DHADn
HIAf5MflCTipQ
/f|Rn

The powertrain control module (PCM) has been
programmed to monitor many different circuits of the
fuel injection system. If a problem is sensed in a monitored circuit often enough to indicate an actual
problem, a diagnostic trouble code (DTC) is stored.
The DTC will be stored in the PCM memory for eventual display to the service technician. If the
problem is repaired or ceases to exist, the PCM can­ cels the DTC after 51 engine starts.
Certain criteria must be met for a diagnostic trou­
ble code (DTC) to be entered into PCM memory. The criteria may be a specific range of engine rpm, en­
gine temperature and/or input voltage to the PCM.
It is possible that a DTC for a monitored circuit
may not be entered into memory even though a mal­
function has occurred. This may happen because one
of the DTC criteria for the circuit has not been met. Example: assume that one of the criteria for the
MAP sensor circuit is that the engine must be oper­ ating between 750 and 2000 rpm to be monitored for
a DTC. If the MAP sensor output circuit shorts to
ground when the engine rpm is above 2400 rpm, a 0
volt input will be seen by the PCM. A DTC will not
be entered into memory because the condition does not occur within the specified rpm range.
A DTC indicates that the powertrain control mod­
ule (PCM) has recognized an abnormal signal in a
circuit or the system. A DTC may indicate the result
of a failure, but never identify the failed component
directly.
There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to
the following Monitored Circuits and Non-Monitored Circuits in this section.

MONITORED
CIRCUITS
The powertrain control module (PCM) can detect
certain problems in the fuel injection system.
Open or Shorted Circuit - The PCM can deter­
mine if sensor output (which is the input to PCM) is
within proper range. It also determines if the circuit is open or shorted.
Output Device Current Flow - The PCM senses
whether the output devices are hooked up.
If there is a problem with the circuit, the PCM
senses whether the circuit is open, shorted to ground
(-), or shorted to
(
+
)
voltage.
Oxygen Sensor - The PCM can determine if the
oxygen sensor is switching between rich and lean.
This is, once the system has entered Closed Loop. Re­ fer to Open Loop/Closed Loop Modes Of Operation in
the Component Description/System Operation section
for an explanation of Closed (or Open) Loop opera­ tion.
NON-MONITORED CIRCUITS

The PCM does not monitor the following circuits,
systems or conditions that could have malfunctions
that result in driveability problems. A diagnostic trouble code (DTC) may not be displayed for these
conditions.
Fuel Pressure: Fuel pressure is controlled by the
vacuum assisted fuel pressure regulator. The PCM
cannot detect a clogged fuel pump inlet filter, clogged
in-line fuel filter, or a pinched fuel supply or return

line.
However, these could result in a rich or lean
condition causing an oxygen sensor DTC to be stored in the PCM.
Secondary Ignition Circuit: The PCM cannot de­
tect an inoperative ignition coil, fouled or worn spark

plugs,
ignition cross firing, or open circuited spark
plug cables.
Engine Timing: The PCM cannot detect an incor­
rectly indexed timing chain, camshaft sprocket or crankshaft sprocket. The PCM also cannot detect an
incorrectly indexed distributor. However, these could
result in a rich or lean condition causing an oxygen
sensor DTC to be stored in the PCM.
Cylinder Compression: The PCM cannot detect
uneven, low, or high engine cylinder compression.
Exhaust System: The PCM cannot detect
a

plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions: The PCM cannot de­
termine if the fuel injector is clogged, or the wrong injector is installed. However, these could result in a
rich or lean condition causing an oxygen sensor DTC
to be stored in the PCM.
Excessive Oil Consumption: Although the PCM
monitors exhaust stream oxygen content through ox­
ygen sensor (closed loop), it cannot determine exces­ sive oil consumption.
Throttle Body Air Flow: The PCM cannot detect
a clogged or restricted air cleaner inlet or air filter
element.
Evaporative System: The PCM will not detect a
restricted, plugged or loaded EVAP canister. Vacuum Assist: Leaks or restrictions in the vac­
uum circuits of vacuum assisted engine control sys­
tem devices are not monitored by the PCM. However, a vacuum leak at the MAP sensor will be monitored
and a diagnostic trouble code (DTC) will be gener­
ated by the PCM.
Powertrain Control Module (PCM) System
Ground: The PCM cannot determine a poor system
ground. However, a DTC may be generated as a re­
sult of this condition.
Powertrain Control Module (PCM) Connector
Engagement: The PCM cannot determine spread or
damaged connector pins. However, a DTC may be generated as a result of this condition.