1999 DODGE RAM Engine control unit

"B" ABBREVIATION TABLE

"B" ABBREVIATION TABLE
ABBREVIATION DEFINITION B/P Backpressure BAC By-Pass Air Control BAP Barometric Absolute Pressure Sensor BARO Barometric BBDC Before Bottom Dead Center BCM Body Control Module BDC Bottom Dead Center BHP Brake Horsepower BLK Black BLU Blue BMAP Barometric & Manifold Absolute Pressure
Sensor BOO Brake On-Off Switch BP Barometric Pressure sensor BPS Barometric Pressure sensor BPT Backpressure Transducer BRN Brown BTDC Before Top Dead Center BTU British Thermal Unit BVSV Bimetallic Switching Valve Baro. Barometric Batt. Battery Bbl. Barrel (Example:4-Bbl.) Blst. Ballast Blwr. Blower Brkr. Breaker

"C" ABBREVIATION TABLE

"C" ABBREVIATION TABLE
ABBREVIATION DEFINITION C Celsius (Degrees) C(3) Computer Controlled Coil Ignition C(4) Computer Controlled Catalytic Converter CANP Canister Purge solenoid CARB California Air Resources Board CAT Catalytic Converter CB Circuit Breaker CBD Closed Bowl Distributor CBVV Carburetor Bowl Vent valve cc Cubic Centimeter CCC Computer Command Control CCD Computer Controlled Dwell CCM Central Control Module CCO Converter Clutch Override CCOT Cycling Clutch Orifice Tube CCW Counterclockwise CDI Capacitor Discharge Ignition CEC Computerized Engine Control CFI Central Fuel Injection CID Cubic Inch Displacement CID Cylinder Identification sensor CIS Continuous Injection System CIS-E Continuous Injection System-Electronic

"E" ABBREVIATION TABLE

“E” ABBREVIATION TABLE
ABBREVIATION DEFINITION EAC Electric Assist Choke _ EACV Electric Air Control Valve _ EBCM Electronic Brake Control Module ECA Electronic Control Assembly ECAT Electronically Controlled Automatic
Transaxle ECM Electronic Control Module ECT Engine Coolant Temperature Sensor ECU Electronic Control Unit or Engine Control
Unit EDF Electric Drive Fan relay assembly EDIS Electronic Distributorless Ignition System EEC Electronic Engine Control EECS Evaporative Emission Control System EEPROM Electronically Erasable PROM EFE Early Fuel Evaporation _ EFI Electronic Fuel Injection _ EGO Exhaust Gas Oxygen sensor (see HEGO) EGR Exhaust Gas Recirculation system _ EGRC EGR Control solenoid or system _ EGRV EGR Vent solenoid or system _ EMR Emission Maintenance Reminder Module ESA Electronic Spark Advance _ ESC Electronic Spark Control _ EST Electronic Spark Timing _ ETR Emergency Tensioning Retractor _ EVAP Fuel Evaporative System _ EVIC Electronic Vehicle Information Center EVO Electronic Variable Orifice _ EVP EGR Valve Position Sensor _ EVR EGR Valve Regulator _ EVRV Electronic Vacuum Regulator Valve Elect. Electronic _ Eng. Engine _ Evap. Evaporative _ Exc. Except _

"F" ABBREVIATION TABLE

"F" ABBREVIATION TABLE
ABBREVIATION DEFINITION F Fahrenheit (Degrees) F/B Fuse Block FBC Feedback Carburetor FI Fuel Injector or Fuel Injection FICD Fast Idle Control Device FIPL Fuel Injector Pump Lever FP Fuel Pump FPM Fuel Pump Monitor FPR-VSV Fuel Pressure Regulator Vacuum Switching
Valve FWD Front Wheel Drive Fed. Federal Ft. Lbs. Foot Pounds

"R" ABBREVIATION TABLE

"R" ABBREVIATION TABLE
ABBREVIATION DEFINITION RABS Rear Anti-Lock Brake System RAC Remote Accessory Control RAM Random Access Memory RAP Retained Accessory Power RECIRC Recirculation RED Red RH Right hand ROM Read Only Memory RPM Revolutions Per Minute RVB Rear Vacuum Break RWAL Rear Wheel Anti-Lock Brake RWD Rear Wheel Drive Recirc. Recirculate or Recirculation Reg. Regulator Rly. Relay

"S" ABBREVIATION TABLE

"S" ABBREVIATION TABLE
ABBREVIATION DEFINITION SAW Spark Angle Word _ SBC Single Bed Converter _ SBEC Single Board Engine Controller _ SC Super Charged _ SCC Spark Control Computer _ SCS Air Suction Control Solenoid _ SDM Supplemental Restraint System Diagnostic Module _ SDU SRS Diagnostic Unit _ SEN Sensor _ SES Service Engine Soon _ SFI Sequential (Port) Fuel Injection _ SIG RTN Signal Return circuit _ SIL Shift Indicator Light _ SIR Supplemental Inflatable Restraint _ SMEC Single Module Engine Controller _ SOHC Single Overhead Cam _ SOL or SoL Solenoid _ SPFI Sequential Port Fuel Injection _ SPK Spark Control _ SPOUT Spark Output Signal _ SRS Supplemental Restraint System (Air Bag) _ SS 3/4-4/3 Shift Solenoid circuit _ SSI Solid State Ignition _ STAR Self-Test Automatic Readout _ STI Self Test Input circuit _ STO Self-Test Output _ SUB-O2 Sub Oxygen Sensor _ Sen. Or Sens. Sensor _ Sol. Solenoid _ Sprchg. Supercharger _ Strg. Steering _ Susp. Suspension _ Sw. Switch _ Sys. System _

be detected if leak testing is performed too quickly.
BUBBLE DETECTOR LEAK TESTING PROCEDURE
This leak detection method is recommended when it is
impossible or difficult to determine the exact location of the leak
using other methods. Although commercial bubble detectors are more
effective, household soap solutions may be used.
Using the dauber that comes with the commercial soap
solution, apply the solution to all joints, connections, fittings or
controls where a leak might be suspected. If high-suds household
solutions are used, apply them with a small brush. Wherever bubbles
form, leaks are present and must be repaired. check the entire system
as there may be more than one leak.
ELECTRONIC LEAK TESTING PROCEDURE
NOTE: Some electronic leak detectors will function on only R-12
systems or on only R-134a systems, and some will function on
both R-12 and R-134a systems. Familiarize yourself with the
tester being used and know what type of system you are leak
testing.
Electronic leak detectors should be used in well ventilated
areas. Avoid using them around explosive gases. Always follow
manufacturer's instructions for the specific tester being used. If
none are available, proceed as follows:
1) Turn all controls and detector sensitivity knob to OFF
position or zero setting. Connect leak detector to an approved source
of power. Turn switch ON, and allow unit to warm up for approximately
5 minutes.
2) Check operation of tester by positioning probe in a
reference source where refrigerant is known to be present in small
amounts. Adjust controls and sensitivity knob until detector reacts
properly. Move probe away from refrigerant source and the reaction
should stop. If it continues, adjust the sensitivity knob to a lower
setting.
3) When tester reacts properly, leak test air conditioning
system by moving probe UNDER all components, fittings and connections.
Keep the probe moving. To check evaporator insert probe into drain
tube opening or a heater duct. DO NOT allow probe to contact
refrigerant or refrigerant oil. When leaks are found, repair them as
necessary. Keep in mind that there may be more than one leak.
DYE SOLUTION LEAK TESTING PROCEDURES
CAUTION: Dye-charged refrigerant cans are available to be used as
internal leak detectors. The use of this type of solution may
void some manufacturer's warranties. Be sure to check with
the A/C system manufacturer concerning the use of dye-charged
leak detectors. Dyes which work in R-12 systems will not work
in R-134a systems.
The following procedure is for introducing a dye solution,
not dye-charged refrigerant, into A/C system.
1) Connect manifold gauge set to air conditioning system in a
normal manner. Remove center hose from manifold gauge set, and replace
it with a short piece (6" long) of 1/4" tubing using two 1/4" flare
nuts. Connect a container of dye solution to the tubing.
2) Connect one end of gauge set center hose to dye solution
container. Connect a container of refrigerant to the other end of the
hose. Operate engine at idle speed. Set the air conditioning system
for maximum cooling. Slowly open the low-side hand valve to allow the

CIRCUIT PROTECTION DEVICES









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Component Component Location








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Circuit Breakers In junction block.
Junction Block Left end of dash.
Power Distribution Center In engine compartment, on left
inner fender panel, near
battery.









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CONTROL UNITS









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Component Component Location








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Air Bag Control Module Behind lower center of dash.
Controller Anti-Lock Brake (4WABS) Engine compartment, mounted on\
top of hydraulic control unit.
Controller Anti-Lock Brake (RWAL) In engine compartment, on left\
front inner fender.
Daytime Running Lamp (DRL) Module In engine compartment, on left\
inner fender panel.
Engine Control Module (Diesel) On left side of engine, behind\
fuel filter.
Fuel Pump Module Top of fuel tank.
Integrated Electronic Module Left side of dash, inboard of
steering column opening.
Powertrain Control Module (PCM) In engine compartment, on
right side of firewall.
Seat Belt Control Module Under front seat center
cushion.









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MOTORS









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Component Component Location








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Blower Motor Behind right side of dash.
Fuel Injection Pump (Diesel) On left side of engine, on
rear of timing gear housing.
Fuel Transfer Pump (Diesel) On left side of engine, below
and rearward of fuel filter.

inspection procedures.
A visual inspection is made to determine if any required
emission control devices are missing, modified or disconnected.
Missing, modified or disconnected systems must be made fully
operational before a vehicle can be certified.
POSITIVE CRANKCASE VENTILATION (PCV)
PCV controls the flow of crankcase fumes into the intake
manifold while preventing gases and flames from traveling in the
opposite direction. PCV is either an open or closed system. See Fig. 2
.
Ensure PCV system is installed as required. Verify valve,
required hoses, connections, flame arresters, etc., are present,
routed properly and in serviceable condition.
Fig. 2: Typical Open & Closed Type PCV System
THERMOSTATIC AIR CLEANER (TAC)
The TAC supplies warm air to air intake during cold engine
operation. This system is active during cold engine warm-up only.
Under all other operating conditions, air cleaner function is the same
as any non-thermostatic unit.
Ensure required exhaust shroud, hot air duct, vacuum hoses
and air cleaner components are present and installed properly. See
Fig. 3 . Ensure any required thermostatic vacuum switches are in place
and vacuum hoses are installed and in serviceable condition. Also
ensure air cleaner lid is installed right side up. Check for oversized
air filter elements and for additional holes in the air cleaner
housing.

Spark control systems are designed to ensure the air/fuel
mixture is ignited at the best possible moment to provide optimum
efficiency and power and cleaner emissions.
Ensure vacuum hoses to the distributor, carburetor, spark
delay valves, thermal vacuum switches, etc., are in place and routed
properly. On Computerized Engine Controls (CEC), check for presence of\
required sensors (O2, MAP, CTS, TPS, etc.). Ensure they have not been
tampered with or modified.
Check for visible modification or replacement of the feedback
carburetor, fuel injection unit or injector(s) with a non-feedback
carburetor or fuel injection system. Check for modified emission-
related components unacceptable for use on pollution-controlled
vehicles.
AIR INJECTION SYSTEM (AIS)
Air Pump Injection System (AP)
The air pump is a belt-driven vane type pump, mounted to
engine in combination with other accessories. The air pump itself
consists of the pump housing, an inner air cavity, a rotor and a vane
assembly. As the vanes turn in the housing, filtered air is drawn in
through the intake port and pushed out through the exhaust port. See
Fig. 13 .
Check for missing or disconnected belt, check valve(s),
diverter valve(s), air distribution manifolds, etc. Check air
injection system for proper hose routing.
Fig. 13: Typical Air Pump Injection System
Courtesy of General Motors Corp.
Pulsed Secondary Air Injection (PAIR) System
PAIR eliminates the need for an air pump and most of the
associated hardware. Most systems consists of air delivery pipe(s),
pulse valve(s) and check valve(s). The check valve prevents exhaust
gases from entering the air injection system. See Fig. 14.
Ensure required check valve(s), diverter valve(s), air
distribution manifolds, etc., are present. Check air injection system
for proper hose routing.

WIRING DIAGRAM COMPONENT LOCATIONS
When trying to locate a component in a wiring diagram and you
don't know the specific system where it is located, use this handy
component locator to find the system wiring diagram in which the
component is located. Then, go to that system and locate the component
within the wiring diagram.
For example, if you don't know the specific system in which
the ignition switch is located, look up ignition switch in the wiring
diagram component location tables and go to the appropriate wiring
diagram(s) which contain either full or partial views of the ignition
switch. The full view of the ignition switch is located in Power
Distribution.
The first listing for the component will be the full or most
complete view of the component. Additional listings will be partial
views of the component. Not all components are used on all models.
All components will have a partial view in Ground
Distribution and Power Distribution. Data Link Connectors show
connecting circuits between modules. Alternate names for components
may be listed in wiring diagram component locations tables.
WIRING DIAGRAM COMPONENT LOCATIONS TABLE









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Component Wiring Diagram
ABS Electronic Control Unit ....................... Anti-Lock Brakes
Data Link Connectors
ABS Hydraulic Unit ................................ Anti-Lock Brakes
Acceleration Sensor ............................... Anti-Lock Brakes
Accessory Delay Relay ................................ Power Windows
A/C Compressor Clutch Relay ..................... Engine Performance
A/C Sensor ...................................... Engine Performance
A/C Pressure Switch ............................. Engine Performance
Adaptive Lamp Control Module ....................... Exterior Lights
Air Bag(s) ................................ Air Bag Restraint System\
Air Bag Module ............................ Air Bag Restraint System
Air Bag Sensor(s) ......................... Air Bag Restraint System\
Air Injection Pump Relay ........................ Engine Performance
Air Temperature Sensor ............................ Overhead Console
Alternator (Generator) ..................... Generators & Regulators\
Anti-Theft Control Module ........................ Anti-Theft System
Starters
Autolamp Control Relay ........................... Headlight Systems
Daytime Running Lights
Automatic Shutdown (ASD) Relay .................. Engine Performance\
Generators & Regulators
Autostick Switch ................................ Engine Performance
Auxiliary Battery Relay .................... Generators & Regulators
Back-Up Lights ...................................... Back-Up Lights
Exterior Lights
Barometric (BARO) Pressure Sensor ............... Engine Performance\
Battery ......................................... Power Distribution
Battery Temperature Sensor ...................... Engine Performance
Body Control Module .......................... Body Control Computer
Anti-Theft System
Daytime Running Lights
Engine Performance
Headlight Systems
Warning Systems
Boost Control Solenoid .......................... Engine Performance
Boost Sensor .................................... Engine Performance
Brake Fluid Level Switch .................. Analog Instrument Panels