2003 DODGE RAM Vacuum

POWERTRAIN CONTROL MODULE C3 (JTEC) - GRAY 32 WAY
CAV CIRCUIT FUNCTION
1 C13 18DB/OR A/C CLUTCH RELAY CONTROL
2- -
3 K51 18DB/YL AUTO SHUT DOWN RELAY CONTROL
4 V36 18TN/RD SPEED CONTROL VACUUM SOLENOID CONTROL
5 V35 18LG/RD SPEED CONTROL VENT SOLENOID CONTROL
6- -
7 K73 18YL/BK (3.7L) KNOCK SENSOR NO. 1 SIGNAL
8 K199 18BR/VT OXYGEN SENSOR 1/1 HEATER CONTROL
9 K127 18DB/OR OXYGEN SENSOR DOWNSTREAM RELAY CONTROL
10 K106 18WT/DG LEAK DETECTION PUMP SWITCH SENSE
11 V32 18YL/RD SPEED CONTROL SUPPLY
12 A142 16DG/OR AUTO SHUT DOWN RELAY OUTPUT
13 T6 18OR/WT (5.9L) OVERDRIVE OFF SWITCH SENSE
13 T10 18YL/DG (5.9L DIESEL) TORQUE MANAGEMENT REQUEST SENSE
14 K107 18OR LEAK DETECTION PUMP SOLENOID CONTROL
15 K118 18PK/YL BATTERY TEMPERATURE SENSOR SIGNAL
16 K299 18BR/WT (CALIFORNIA) OXYGEN SENSOR 2/1 HEATER CONTROL
16 K299 18BR/WT (EXCEPT CALIFORNIA) OXYGEN SENSOR 1/2 HEATER CONTROL
17 - -
18 K74 18BR/VT (3.7L) KNOCK SENSOR NO. 2 SIGNAL
19 K31 18BR FUEL PUMP RELAY CONTROL
20 K52 18PK/BK EVAPORATIVE EMISSION SOLENOID CONTROL
21 - -
22 - -
23 - -
24 K29 18WT/PK BRAKE SWITCH SENSE
25 K125 18WT/DB GENERATOR SOURCE
26 G8 18LB/BK FUEL LEVEL SENSOR SIGNAL
27 D21 18PK SCI TRANSMIT
28 - -
29 D20 18LG SCI RECEIVE
30 D25 18VT/BR PCI BUS
31 - -
32 V37 18RD/LG SPEED CONTROL SWITCH SIGNAL
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 91

POWERTRAIN CONTROL MODULE C3 (NGC) - WHITE 38 WAY
CAV CIRCUIT FUNCTION
1- -
2- -
3 K51 20DB.YL ASD RELAY CONTROL
4- -
5 V35 18LG/RD (4.7L) S/C VENT CONTROL
6 Y145 20DB/YL CONDENSER FAN RELAY CONTROL
7 V32 20YL/RD (4.7L) S/C POWER SUPPLY
8 K106 18WT/DG (4.7L) NVLD SOLENOID CONTROL
9 K199 18BR/VT O2 1/2 HEATER CONTROL
10 K399 18BR/GY (4.7L) O2 2/2 HEATER CONTROL
11 C13 20DB/OR A/C CLUTCH RELAY CONTROL
12 V36 18TN/RD (4.7L) S/C VACUUM CONTROL
13 - -
14 V32 20YL/RD (5.7L) BRAKE SWITCH NO.2 SIGNAL
15 Y215 20YL/PK (5.7L) S/C SWITCH RETURN
16 K223 18PK/DB (5.7L) APPS NO.1 RETURN
17 K981 18BR/DG (5.7L) APPS NO.2 RETURN
18 V38 20VT/OR (5.7L) S/C SWITCH NO.2 SIGNAL
19 A142 16DG/OR ASD RELAY OUTPUT
20 K108 18WT/TN EVAP PURGE SOL SIGNAL
21 T24 20BR/YL TRS T24 SENSE (P/N SENSE)
22 G113 18OR PTO SWITCH SENSE
23 K29 18WT/PK BRAKE SWITCH SIGNAL
24 - -
25 K255 18WT/DG (5.7L) APPS NO.1 SIGNAL
26 - -
27 - -
28 A142 16DG/OR ASD RELAY OUTPUT
29 K52 18PK/BK EVAP PURGE SOL CONTROL
30 S28 18YL/BK P/S SWITCH SIGNAL
31 - -
32 K118 18PK/YL BATT TEMP SIGNAL
33 G8 18LB/BK FUEL LEVEL SIGNAL
34 V37 18RD/LG S/C SWITCH NO.1 SIGNAL
35 K107 18OR NVLD SWITCH SIGNAL
36 K81 18DB/DG (5.7L) APPS NO.2 SIGNAL
37 K31 18BR FUEL PUMP RELAY CONTROL
38 T752 18DG/OR STARTER RELAY CONTROL
8W - 80 - 92 8W-80 CONNECTOR PIN-OUTSDR

SPEAKER-RIGHT FRONT DOOR - WHITE 3 WAY
CAV CIRCUIT FUNCTION
1 X80 18LB/BK RIGHT FRONT DOOR SPEAKER (-)
2- -
3 X82 18LB/VT RIGHT FRONT DOOR SPEAKER (+)
SPEAKER-RIGHT INSTRUMENT PANEL - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 X84 18OR/BK RIGHT INSTRUMENT PANEL SPEAKER (+)
2 X86 18OR/RD RIGHT INSTRUMENT PANEL SPEAKER (-)
SPEAKER-RIGHT REAR - WHITE 3 WAY
CAV CIRCUIT FUNCTION
1 X94 18TN/VT RIGHT REAR SPEAKER (+)
2- -
3 X92 18TN/BK RIGHT REAR SPEAKER (-)
SPEED CONTROL SERVO - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 V36 20TN/RD SPEED CONTROL VACUUM SOLENOID CONTROL
1 V36 20TN/RD (NGC) S/C VACUUM CONTROL
2 V35 20LG/RD (NGC) S/C VENT CONTROL
2 V35 20LG/RD SPEED CONTROL VENT SOLENOID CONTROL
3 V30 20DB/RD SPEED CONTROL BRAKE SWITCH OUTPUT
3 V30 20DB/RD (NGC) S/C BRAKE SWITCH OUTPUT
4 Z10 20BK/TN GROUND
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 97

TRANSMISSION SOLENOID/TRS ASSEMBLY (3.7L/4.7L/5.7L) - BLACK 23 WAY
CAV CIRCUIT FUNCTION
1 L10 18BR/LG FUSED IGNITION SWITCH OUTPUT (RUN)
2 T120 18LG LR SOLENOID CONTROL
3 T24 18BR/YL TRS T41 SENSE
4 T41 18BK/WT (5.7L) TRS T41 SENSE
4 T24 20BR/YL (4.7L) TRS T41 SENSE
5 T42 18VT/WT TRS T42 SENSE
6 L1 18VT/BK BACK-UP LAMP FEED
7 T60 18BR OVERDRIVE SOLENOID CONTROL
8 T3 18VT TRS T3 SENSE
9 T1 18LG/BK TRS T1 SENSE
10 T16 16RD TRANSMISSION CONTROL RELAY OUTPUT
11 T48 18DB 4C PRESSURE SWITCH SENSE
12 T118 18YL/DB PRESSURE CONTROL SOLENOID CONTROL
13 T4 18PK/OR TRS T2 SENSE
14 T50 18DG LOW/REVERSE PRESSURE SWITCH SENSE
15 T147 18LB 2C PRESSURE SWITCH SENSE
16 T9 18OR/BK OVERDRIVE PRESSURE SWITCH SENSE
17 T59 18PK UNDERDRIVE SOLENOID CONTROL
18 T29 18GY UNDERDRIVE PRESSURE SWITCH SENSE
19 T159 18DG/WT 4C SOLENOID CONTROL
20 T119 18WT/DB 2C SOLENOID CONTROL
21 T140 18VT/LG PRESSURE CONTROL SOLENOID CONTROL
22 T13 18DB/BK (5.7L) SPEED SENSOR GROUND
22 K4 18BK/LB (4.7L) SENSOR GROUND
23 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
UNDERHOOD LAMP - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 Z235 20LB/BK GROUND
2 M1 18PK FUSED B(+)
VACUUM PUMP (DIESEL)-4WAY
CAV CIRCUIT FUNCTION
1- -
2 Y135 18LG/BK FUSED IGNITION SWITCH OUTPUT (RUN-START)
3- -
4 Z11 18BK/WT GROUND
8W - 80 - 106 8W-80 CONNECTOR PIN-OUTSDR

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Manifold Absolute Pressure Sensor
(5.9L)BK Left Front of Intake Manifold 8
Mode Door Actuator 1 BK Right Side of HVAC N/S
Mode Door Actuator 2 BK Right Side of HVAC N/S
Multi-Function Switch BK On Steering Column N/S
Natural Vacuum Leak Detection
AssemblyBK Rear of Transmission 18, 19
Output Speed Sensor DB Left Side of Transmission 11, 12, 14, 15
Overdrive Switch WT Center of Instrument Panel 37
Overhead Map/Reading Lamp
(Except Base)NAT Center of Headliner N/S
Oxygen Sensor 1/1 Upstream BK Left Front of Side of Transmission 11, 12, 14, 16
Oxygen Sensor 1/2 Downstream NAT Left Rear of Side of Transmission 11, 14, 16
Oxygen Sensor 2/1 Upstream BK Right Front Side of Transmission 11, 12, 14, 16, 17, 18,
19
Oxygen Sensor 2/2 Downstream BK Right Rear Side of Transmission 11, 12, 14, 16, 17, 18,
19
Park Brake Switch At Park Brake 26, 27
Park/Turn Signal Lamp-Left Front BK At Lamp 26, 30, 31
Park/Turn Signal Lamp-Right Front BK At Lamp 1, 25, 29
Passenger Airbag On/Off Switch Right Side of Instrument Panel 35, 37, 40
Passenger Blend Door Actuator
(Dual Zone)BK Right Side of HVAC N/S
Passenger Lumbar Switch At Passenger Seat N/S
Power Mirror-Left BK At Mirror 42
Power Mirror-Right BK At Mirror N/S
Power Outlet RD Center of Instrument Panel 37
Power Outlet-Console BK Center of Instrument Panel N/S
Power Seat Motor-Driver Front
VerticalRD At Driver Seat N/S
Power Seat Motor-Driver Horizontal BK At Driver Seat N/S
Power Seat Motor-Driver Rear
VerticalBK At Driver Seat N/S
Power Seat Switch-Driver BK At Driver Seat N/S
Power Seat Switch-Passenger BK At Passenger Seat N/S
Power Steering Pressure Switch BK Near Power Steering Pump 4, 5
Power Window Circuit Breaker Under Instrument Panel 33, 37, 39
Power Window Motor-Driver BK In Driver Door at Motor 42
Power Window Motor-Left Rear BK In Door at Motor 43
Power Window Motor-Passenger BK In Passenger Door at Motor N/S
Power Window Motor-Right Rear BK In Door at Motor 43
Power Window Switch-Left Rear BL In Door 43
Power Window Switch-Right Rear BL In Door 43
Powertrain Control Module C1 BK Right Rear Engine Compartment 21, 22, 23, 24
8W - 91 - 6 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONDR
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)ÐPERFORMANCE and (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)ÐMECHANICAL for
possible causes and corrections of malfunctions.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING) and (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION - DIAGNOSIS
AND TESTING) for the fuel system diagnosis.Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING).
²Engine Cylinder Head Gasket Failure Diagnosis
(Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNO-
SIS AND TESTING).
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery 1. Charge or replace as necessary.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. Faulty starter. 3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. Faulty coil or control unit. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
5. Incorrect spark plug gap. 5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
6. Incorrect right bank cam timing. 6. Refer to engine timing in this
section.
7. Dirt or water in fuel system. 7. Clean system and replace fuel
filter.
8.Faulty fuel pump, relay or wiring. 8.Repair or replace as necessary.
9. Faulty cam or crank sensor 9. Refer to Ignition system.
ENGINE STALLS OR ROUGH IDLE 1. Vacuum leak. 1. Inspect intake manifold and
vacuum hoses, repair or replace as
necessary.
2. Faulty crank position sensor 2. Replace crank position sensor.
3. Faulty coil. 3. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9 - 4 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

(12) Disconnect heater hoses from heater core and
remove hose assembly.
(13) Disconnect throttle and speed control cables.
(14) Remove upper radiator hose from engine.
(15) Remove lower radiator hose from engine.
(16) Remove radiator/cooling module assembly.
(17) Disconnect the engine to body ground straps
at the left side of cowl.
(18) Disconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(19) Remove coil over plugs.
(20) Release fuel rail pressure.
(21) Remove fuel rail and secure away from
engine.
NOTE: It is not necessary to release the quick con-
nect fitting from the fuel supply line for engine
removal.
(22) Remove the PCV hose.
(23) Remove the breather hoses.
(24) Remove the vacuum hose for the power brake
booster.
(25) Disconnect knock sensors.
(26) Remove engine oil dipstick tube.
(27) Remove intake manifold.
(28) Install engine lifting fixture,special tool#8247,
using original fasteners from the removed intake
manifold, and fuel rail. Torque to factory specifica-
tions.
NOTE: Recheck bolt torque for engine lift plate
before removing engine.
(29) Secure the left and right engine wiring har-
nesses away from engine.
(30) Raise vehicle.
(31) Disconnect oxygen sensor wiring.
(32) Disconnect crankshaft postion sensor.
(33) Disconnect the engine block heater power
cable, if equipped.
(34) Disconnect the front propshaft at the front
differential and secure out of way.
NOTE: It is necessary to disconnect the front prop-
shaft for access to the starter and left side exhaust
flange.(35) Remove the starter.
(36) Remove the ground straps from the left and
right side of the block.
(37) Disconnect the right and left exhaust pipes at
the manifolds and from the crossover, and remove
from the vehicle.
NOTE: The exhaust clamps at the manifolds cannot
be reused. New clamps must be used or leaks may
occur.
(38) Remove the structural cover.
(39) Remove torque convertor bolts, and mark
location for reassembly.
(40) Remove transmission bellhousing to engine
bolts.
(41) Remove left and right engine mount thru
bolts.
(42) Lower the vehicle.
(43) Support the transmission with a suitable jack.
(44) Connect a suitable engine hoist to the engine
lift plate.
(45) Remove engine from vehicle.
INSTALLATION
(1) Position the engine in the vehicle.
(2) Install both left and right side engine mounts
onto engine.
(3) Raise the vehicle.
(4) Install the transmission bellhousing to engine
mounting bolts. Tighten the bolts to 41 N´m (30ft.
lbs.).
(5) Tighten the engine mount thru bolts.
(6) Install the torque convertor bolts.
(7) Connect the ground straps on the left and right
side of the engine.
(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
NOTE: New clamps must be used on exhaust man-
ifold flanges. Failure to use new clamps may result
in exhaust leaks.
(12) Install the left and right exhaust pipes.
(13) Connect the left and right oxygen sensors.
(14) Lower vehicle.
(15) Remove the engine lift plate.
(16) Connect the knock sensors.
DRENGINE - 3.7L 9 - 11
ENGINE - 3.7L (Continued)

(17) Connect the engine to body ground straps at
the left side of the cowl.
(18) Install the intake manifold.
(19) Install the engine oil dipstick tube.
(20) Install the power brake booster vacuum hose.
(21) Install the breather hoses.
(22) Install the PCV hose.
(23) Install the fuel rail.
(24) Install the coil over plugs.
(25) Connect the engine wiring harness at the fol-
lowing points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(26) Reinstall the radiator/cooling module assem-
bly.
(27) Connect lower radiator hose.
(28) Connect upper radiator hose.
(29) Connect throttle and speed control cables.
(30) Install the heater hose assembly.
(31) Install coolant recovery bottle.
(32) Install the power steering pump.
(33) Install the generator.
(34) Install the A/C compressor.
(35) Install the drive belt.
(36) Install the fan shroud with the viscous fan
assembly.
(37) Install the radiator core support bracket.
(38) Install the air cleaner assembly.
(39) Refill the engine cooling system.
(40) Recharge the air conditioning.
(41) Install the hood.
(42) Check and fill engine oil.
(43) Connect the battery negative cable.
(44) Start the engine and check for leaks.SPECIFICATIONS
SPECIFICATIONS ± 3.7L ENGINE
DESCRIPTION SPECIFICATION
Engine Type 90É SOHC V-6 12-Valve
Displacement 3.7 Liters / 3700 cc
226 ( Cubic Inches)
Bore 93.0 mm (3.66 in.)
Stroke 90.8 mm (3.40 in.)
Compression Ratio 9.1:1
Horsepower 210 BHP @ 5200 RPM
Torque 225 LB-FT @ 4200 RPM
Lead Cylinder #1 Left Bank
Firing Order 1-6-5-4-3-2
CYLINDER BLOCK
Cylinder Block Cast Iron
Bore Diameter 93.0   .0075 mm
(3.6619   0.0003 in.)
Out of Round (MAX) 0.076 mm (0.003 in.)
Taper (MAX) 0.051 mm (0.002 in.)
PISTONS
Material Aluminum Alloy
Diameter 92.975 mm (3.6605 in.)
Weight 367.5 grams (12.96 oz)
Ring Groove Diameter
No. 1 83.73 - 83.13 mm
(3.296 - 3.273 in.)
No. 2 82.833 - 83.033 mm
(3.261 - 3.310 in.)
No. 3 83.88 - 84.08 mm
(3.302 - 3.310 in.)
PISTON PINS
Type Floating
Clearance In Piston 0.006 - 0.015 mm
(0.0002 - 0.0005 in.)
Diameter 24.017 - 24.020 mm
(0.9455 - 0.9456 in.)
PISTON RINGS
Ring Gap
Top Compression Ring 0.20 - 0.36 mm
(0.0079 - 0.0142 in.)
9 - 12 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)