1999 DODGE RAM Service Repair Manual

ADJUSTING SEQUENCE table. Using feeler gauge, check valve clearance
between rocker arm socket and crosshead. Ensure valve clearance is
within specification. See VALVE CLEARANCE SPECIFICATIONS table. If
valve clearance is within specification, go to next step. If any valve
clearance is not within specification, loosen rocker lever adjusting
screw lock nut, and adjust valve clearance by rotating rocker lever
adjusting screw. Tighten rocker lever adjusting screw lock nut to
specification. See TORQUE SPECIFICATIONS. When all valve clearances
are within specification, go to next step.
Fig. 2: Identifying Fuel Pump Gear Timing Mark Orientation
Courtesy of Chrysler Corp.
VALVE CLEARANCE ADJUSTING SEQUENCE









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Procedure Cylinders No.
Step 1 (1)
Intake Valve ............................................ 1, 2 & 4
Exhaust Valve ........................................... 1, 3 & 5
Step 2 ( 2)
Intake Valve ............................................ 3, 5 & 6
Exhaust Valve ........................................... 2, 4 & 6
( 1) - Perform STEP 1. See Fig. 2.
( 2) - Rotate engine clockwise (viewed from front of engine) one full
revolution from TDC on cylinder No. 1 (STEP 1) and align
reference marks. Perform STEP 2. See Fig. 2.









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VALVE CLEARANCE SPECIFICATIONS ( 1)








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Application In. (mm)\
Intake Valve ............................. ( 2) .006-.015 (.152-.381)
Exhaust Valve ............................ ( 3) .015-.030 (.381-.762)
( 1) - Adjust valve clearance with engine temperature less than
140
F (60C).
( 2) - Set to .010" (.254 mm) if adjustment is necessary.
( 3) - Set to .020" (.508 mm) if adjustment is necessary.









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3) Rotate engine clockwise (viewed from front of engine) one\
full revolution from TDC on cylinder No. 1 and align reference marks.
Check valve clearance on proper valves. Perform STEP 2. See Fig. 2.
See VALVE CLEARANCE ADJUSTING SEQUENCE table. Ensure valve clearance
is within specification. See VALVE CLEARANCE SPECIFICATIONS table. If
valve clearance is within specification, go to next step. If valve
clearance is not within specification, loosen rocker lever adjusting
screw lock nut, and adjust valve clearance by rotating rocker lever
adjusting screw. Tighten rocker lever adjusting screw lock nut to
specification. See TORQUE SPECIFICATIONS. Go to next step.
4) Install valve cover, fuel pump access cover and battery
cables.
FUEL INJECTION PUMP TIMING
CHECKING FUEL INJECTION PUMP TIMING
NOTE: With Bosch VP 44 pump, no mechanical adjustments are
necessary. All timing and fuel adjustments are performed by
Engine Control Module (ECM). If a FTC indicating engine sync
error or static timing error has been set, perform following
adjustment. If FTC sets after installing a new pump, pump
keyway has probably been installed backward.
CAUTION: DO NOT allow nut and washer to fall inside front cover.
1) Remove fuel pump access cover, shaft nut and washer.
Ensure keyway aligning pump shaft to pump gear has not slipped. If
keyway has slipped, repair as necessary.
2) Remove timing gear cover. See REMOVAL, OVERHAUL &
INSTALLATION - TRUCKS - DIESEL article. Using a T-type puller, remove
injection pump gear from shaft. Ensure key has been installed in
keyway with arrow pointing to rear of pump. Pump timing is calibrated
to pump keyway. Ensure 3-digit number on key matches number on pump

data plate. See Fig. 3. There are 21 different calibrations available.
Repair as necessary.
Fig. 3: Identifying Pump Keyway & Pump Data Plate
Courtesy of Chrysler Corp.
3) Reinstall pump timing gear. Ensure timing marks on
crankshaft gear, camshaft gear and fuel pump gear are aligned. See

Fig. 4. Repair as necessary. After repairs are done, clear DTCs.
Fig. 4: Identifying Timing Gear Marks
Courtesy of Chrysler Corp.
IDLE SPEED
Idle speed is controlled by Engine Control Module (ECM). Idle\
speed is not adjustable.
THROTTLE POSITION SENSOR
THROTTLE POSITION SENSOR ADJUSTMENT
Throttle position sensor may also be referred to as
Acceleration Pedal Position Sensor (APPS). Throttle Position (TP)
sensor is not adjustable.










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AIR B AG R ESTR AIN T S YSTE M
1999 D odge P ic ku p R 1500
1999 AIR BAG RESTRAINT SYSTEMS
DaimlerChrysler Corp.
Dodge: Ram Pickup
DESCRIPTION & OPERATION
* PLEASE READ THIS FIRST *
WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all WARNINGS and SERVICE PRECAUTIONS.
Supplemental Restraint System (SRS) is designed to work in
conjunction with seat belts. SRS helps to reduce the risk or severity
of serious injury during a front-end collision. Driver-side air bag is
stored in a module in steering wheel hub. All models are equipped with
passenger-side air bags. Passenger-side air bag is stored in the
instrument panel, above glove box. All air bags are covered by a pad
bearing the air bag SRS logo.
Air bag(s) inflate and deflate within 1/10th of a second of
impact sensor switches closing. This creates a cushion of air between
driver and steering wheel and passenger and instrument panel.
System consists of an AIR BAG warning light, clockspring,
driver-side and passenger-side air bag modules, Air Bag Control Module
(ACM), one impact sensor (located inside ACM) and an energy reserve
capacitor. The ACM monitors system, stores fault codes (messages) and
provides information to AIR BAG warning light and Data Link Connector
(DLC). When a malfunction occurs, a fault code is stored and AIR BAG
warning light is activated for more than 12 seconds.
When impact sensor registers sufficient deceleration force
during a front-end collision, an electrical charge is sent from ACM to
air bag module inflator via the clockspring. Inflator actuates and
produces nitrogen gas, which inflates air bag(s).
AIR BAG WARNING LIGHT
Whenever ignition switch is in RUN or START position, AIR BAG
warning light on instrument panel will illuminate for 6-8 seconds and
then turn off. This signifies ACM has checked the system and found
that it is functioning properly. If AIR BAG warning light illuminates
for 12 seconds or more, stays on all the time or does not come on, a
system malfunction exists and trouble code will be stored.
IMPACT SENSOR
All models have one impact sensor located inside ACM. Impact
sensor is an accelerometer that measures deceleration. During a front-
end collision, a signal is sent that completes an electrical circuit
to inflators. Inflators actuate and produce nitrogen gas, which
inflates each air bag. Impact sensor is calibrated for a specific
vehicle and react to severity and direction of vehicle impact.
AIR BAG MODULE
WARNING: DO NOT attempt to disassemble air bag modules. Air bag
modules are not serviceable.
Driver-Side
Air bag module is mounted on front face of steering wheel. A

protective cover is fitted to front of air bag module bearing the SRS
air bag logo. Air bag module contains air bag cushion, inflator and
supporting components. Air bag module is a sealed unit and is not
serviceable. The module inflator assembly produces nitrogen gas to
fill air bag cushion when a small amount of current from ACM is
applied to the ignitor assembly. Gas pressure builds and discharges
from inflator through a diffuser and screen assembly, forcing steering
wheel cover to burst along its seams until air bag is fully inflated.
Once air bag cushion is fully inflated, gas escapes from bag through
vents, away from driver.
Passenger-Side
Air bag module is mounted to instrument panel mounting
bracket. Module is covered by a protective door bearing the SRS air
bag logo. When supplied an electrical signal, inflator will discharge
argon gas directly into air bag. When air bag inflates, protective
door will pivot aside allowing air bag to deploy.
AIR BAG CONTROL MODULE (ACM)
ACM is located under instrument panel, on transmission
tunnel. Impact sensor, energy reserve capacitor and On-Board
Diagnostics (OBD) are an integral part of ACM. ACM monitors critical
input and output circuits within air bag system, ensuring they are
operating correctly. Some circuits are tested continuously; others are
checked only under certain conditions. ACM provides information about
air bag system through AIR BAG warning light and Data Link Connector
(DLC). When diagnostic trouble code (fault message) is stored, AIR B\
AG
warning light will be activated for 12 seconds or more.
DATA LINK CONNECTOR (DLC)
DLC is located under left side of instrument panel, left of
steering column. DLC is used to access SRS on-board diagnostics.
CLOCKSPRING
Clockspring connects air bag module to steering column
wiring, completing air bag system circuit. See Fig. 1. Inside
clockspring is a flat, ribbon-like tape of conductive material, which
winds and unwinds with steering wheel movement. Clockspring is the
most fragile part of air bag system. Clockspring must be centered
properly to allow 1 1/2 steering wheel turns in either direction. If
clockspring is not centered properly, it can break from stretching or
fatigue.
Fig. 1: Identifying Clockspring Assembly
Courtesy of DaimlerChrysler Corp.

PASSENGER AIR BAG DISARM (PAD) SWITCH
PAD switch is mounted on instrument panel. Switch allows
passenger-side airbag module to be disarmed when rear facing child
safety seat is being used. PAD switch is operated with ignition key.
SYSTEM OPERATION CHECK
Turn ignition on and observe AIR BAG warning light. AIR BAG
warning light should illuminate for 6-8 seconds and then go out,
indicating system is functioning properly. If AIR BAG warning light
either fails to illuminate or illuminates continuously, a system
malfunction exists. Perform self-diagnostics. See DIAGNOSIS & TESTING.
After completing necessary repairs, turn ignition switch to
ON position. Ensure no one is inside vehicle, then connect negative
battery cable. Using DRB, erase stored Diagnostic Trouble Codes (DTC).\
See DIAGNOSIS & TESTING .
SERVICE PRECAUTIONS
These precautions should be observed when working with air
bag systems:
* Disable air bag system before servicing any air bag system
or steering column component. Failure to do this could
result in accidental air bag deployment and possible
personal injury. See DISABLING & ACTIVATING AIR BAG SYSTEM .
* Back-up power supply maintains deployment voltage for about
2 minutes after battery is disconnected. When disabling air
bag system, always wait at least 2 minutes after
disconnecting battery cables to resume procedure.
* After repairs, ensure AIR BAG warning light works
properly and no system faults are indicated. See
SYSTEM OPERATION CHECK .
* Always wear safety glasses when servicing or handling an
air bag.
* All SRS component fasteners are specially coated and are
designed with a specific function. Never replace SRS
component fasteners with other than original equipment parts.
* Air bag module must be stored in its original special
container until used for service. It must be stored in a
clean, dry, place, away from sources of extreme heat, sparks
and high electrical energy.
* When placing a live air bag on a bench or other surface,
always face air bag and trim cover up, away from surface.
This will reduce motion of module if accidentally deployed.
* After deployment, air bag surface may contain deposits of
sodium hydroxide, which irritates skin. Always wear safety
glasses, rubber gloves, and long-sleeved shirt during
clean-up and wash hands using mild soap and water. Follow
correct disposal procedures. See DISPOSAL PROCEDURES.
* Because of critical system operating requirements, DO NOT
attempt to service any air bag components. Corrections are
only made by replacing defective part.
* Electrical sources should never be allowed near inflator on
back of air bag module.
* When carrying a live air bag module, trim cover should be
pointed away from your body to minimize injury in case of
deployment.
* When testing voltage or continuity at Air Bag Control Module

(ACM), use wire side (not terminal end) of connector.
* DO NOT probe a wire through insulator, as this will damage
it and eventually cause failure.
* When performing electrical tests, prevent accidental
shorting of terminals. Such shorts can damage fuses or
components and may cause a second fault code to set, making
diagnosis of original problem more difficult.
* When diagnosing air bag system, use DRB volt/ohmmeter
unless instructed to use an external volt/ohmmeter. NEVER
use an analog volt/ohmmeter or test light in place of a
digital volt/ohmmeter.
* When using DRB to diagnose an air bag system problem,
operate DRB from outside of vehicle. DO NOT sit inside of
vehicle.
* Never use an ohmmeter to measure resistance of air bag
module. Accidental air bag deployment may occur, causing
personal injury.
* If air bag system is not fully functional for any reason,
vehicle should not be driven until system is repaired and
again becomes operational. DO NOT remove bulbs, modules,
sensors, or other components or in any way disable system
from operating normally. If air bag system is not
functional, park vehicle until it is repaired and functions
properly.
* When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may
exist until computer systems have completed a relearn cycle.
See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION
before disconnecting battery.
DISABLING & ACTIVATING AIR BAG SYSTEM
WARNING: Wait at least 2 minutes after disconnecting negative battery
cable before servicing air bag system. System reserve
capacitor, integral to ACM, maintains air bag system voltage
for about 2 minutes after battery is disconnected. Servicing
air bag system before 2-minute period may cause accidental
deployment of air bag(s) and possible personal injury. DO NOT\
use computer system memory saving devices. Enough voltage to
deploy air bag(s) may be provided from device.
CAUTION: When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may
exist until computer systems have completed a relearn cycle.
See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION
before disconnecting battery.
Disabling System
To disable air bag system for repairs, ensure ignition switch
is in OFF position. Disconnect and shield negative battery cable.
After disconnecting negative battery cable, wait at least 2 minutes
for reserve capacitor to discharge before servicing air bag system.
Activating System
Reconnect negative battery cable. From a position clear of air bag(s),\
turn ignition on. Perform system operation check. See
SYSTEM OPERATION CHECK .
DISPOSAL PROCEDURES
DEPLOYED AIR BAG CLEAN-UP