DLC DODGE RAM 1999 Service Repair Manual

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vacuum reading of 26 in. Hg or more. Close all valves and turn vacuum
pump off. Observe vacuum gauge, go to next step.
2) If A/C system maintains specified vacuum for 5 minutes,
open low-side and high-side valves, restart vacuum pump and operate
for an additional 10 minutes. Close all valves. Turn vacuum pump off
and disconnect pump.
3) If A/C system cannot get to or maintain specified vacuum,
check for a defective vacuum pump or leak in A/C system or gauge set.
See LEAK TESTING. Repair or replace components as necessary.
CHARGING A/C SYSTEM
* PLEASE READ THIS FIRST *
CAUTION: During charging of A/C system, refrigerant container must be
in an upright position. If refrigerant container is
upside down, compressor may be damaged by liquid refrigerant
drawn into A/C system.
CHRYSLER CORP.
Avenger 2.0L & Sebring Coupe 2.0L
1) Ensure A/C system has no leaks and has been evacuated. See
EVACUATING A/C SYSTEM and LEAK TESTING. Locate sight glass on
receiver-drier and ensure it is clean. Close low-pressure adapter
valve and remove from manifold gauge set.
2) Connect low-pressure adapter valve to refrigerant
container and open container valve. Ensure Blue charging hose is
properly connected to vehicle low-pressure service valve. Open adapter
valve.
3) If refrigerant is not drawn in, fully close adapter valve
and check for hose connection leaks. If leak is detected, retighten
connections and repeat A/C system evacuation. See EVACUATING A/C
SYSTEM.
4) If refrigerant is drawn in, start engine. Turn A/C on and
set temperature control to maximum cold and blower motor to low speed.
Operate engine at 1500 RPM. As refrigerant is drawn into system, foam
or bubbles will appear in sight glass.
5) System charge will be close to full when sight glass is
clear, compressor clutch is engaged, and compressor suction and
discharge line temperatures are similar. System charge will be
complete when sight glass is clear, compressor clutch is engaged,
compressor discharge line is warm and suction line is cool.
6) When proper amount of refrigerant has been added, stop
engine. Close refrigerant container and adapter valve, and disconnect
gauge set.
Breeze, Cirrus, Concorde, Intrepid, LHS, Stratus & 300M (Scan
Tool Method)
1) Attach Diagnostic Readout Box (DRB) to Data Link Connecto\
r
(DLC). Set DRB (scan tool) to PARTIAL CHARGE TEST. Attach clamp-on
Thermocouple (80PK-1A) to liquid line, as close to condenser outlet as\
possible.
2) Set parking brake, and place transaxle in Park position.
Start engine and allow to idle. Set A/C controls to outside air, panel
mode, full cool, and high blower speed. Turn A/C on, and open vehicle
windows. Operate A/C system for a few minutes to allow system to
stabilize.
3) Place cardboard over front grille area, to block airflow
through part of condenser, to set A/C system pressure to 260 psi (18.3
kg/cm
). This will stop cooling fans from alternating speeds and
maintain constant pressure.

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D - A D JU STM EN TS - C NG & G ASO LIN E

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - On-Vehicle Adjustments - Trucks & RWD Vans - CNG & Gas
Dakota, Durango, Ram Pickup, Ram Van, Ram Wagon
ENGINE MECHANICAL
Before performing any on-vehicle adjustments to fuel or
ignition systems, ensure engine mechanical condition is okay.
VALVE CLEARANCE
NOTE: All engines use hydraulic lifters. No adjustments are
required.
IGNITION TIMING
On all models, ignition timing is controlled by Powertrain
Control Module (PCM). Ignition timing is nonadjustable. DO NOT attempt\
to adjust ignition timing by rotating distributor.
NOTE: On Dakota 3.9L, 5.2L and 5.9L, Durango, Ram Pickup, Ram Van
and Ram Wagon, if distributor is rotated, fuel system
synchronization will be changed. If distributor is removed or
rotated, check fuel system synchronization. See procedures
under FUEL SYSTEM SYNCHRONIZATION under FUEL SYSTEM.
FUEL SYSTEM
FUEL SYSTEM SYNCHRONIZATION
NOTE: Fuel system synchronization is controlled by position of the
distributor. Rotating distributor WILL NOT change ignition
timing, but will change fuel system synchronization. Fuel
system synchronization should be checked anytime distributor
is removed or rotated.
Dakota 3.9L, 5.2L & 5.9L, Durango, Ram Pickup, Ram Van & Ram
Wagon
1) Connect scan tool to Data Link Connector (DLC). DLC is
located below driver's side of instrument panel, near steering column.
See Fig. 1 , 2 or 3.
2) Using scan tool manufacturer's instructions, access SET
SYNC display on scan tool. Following scan tool displays, start engine.
Warm engine to normal operating temperature. Vehicle must be in closed
loop. With engine idling, if scan tool displays IN RANGE along with
0
, this indicates correct distributor location. The degree reading
displayed on scan tool indicates the fuel synchronization, not
ignition timing.
3) If scan tool display is correct, shut engine off. Remove
scan tool. If scan tool does not display IN RANGE along with 0
, go to
next step.
4) If scan tool displays a plus (+) or minus (-) sign next\
to
the degree number, and/or the degree number displayed is not zero,
loosen but DO NOT remove distributor hold-down bolt.
5) Rotate distributor until scan tool displays IN RANGE.
Continue to rotate distributor until a reading as close as possible to

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0 is obtained. Tighten distributor hold-down bolt to 16 ft. lbs. (22
N.m). Shut engine off. Remove scan tool.
Fig. 1: Locating Data Link Connector (DLC) (Dakota & Durango)
Courtesy of Courtesy of Chrysler Corp.
Fig. 2: Locating Data Link Connector (DLC) (Ram Pickup)
Courtesy of Courtesy of Chrysler Corp.

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Fig. 3: Locating Data Link Connector (DLC) (Ram Van & Ram Wagon)
Courtesy of Courtesy of Chrysler Corp.
IDLE SPEED & MIXTURE
Idle speed and mixture are controlled by Powertrain Control
Module (PCM). No adjustment is required. PCM controls Idle Air Control\
(IAC) motor for proper idle speed. See SELF-DIAGNOSTICS - JEEP, TRUCKS\
& RWD VANS article for diagnosis of incorrect idle speed or IAC motor
operation.
THROTTLE BODY MINIMUM AIRFLOW
NOTE: Throttle body minimum airflow procedure checks throttle body
calibration for correct idle speed. Procedure may be used for
idle speed problems caused by the throttle body. Throttle
body minimum airflow procedure should be performed after all
other diagnostic procedures have failed to produce results
that indicate a throttle body related problem. Ensure IAC
motor is operating correctly before performing this
procedure.
Dakota, Durango, Ram Pickup, Ram Van & Ram Wagon
1) Start engine and warm engine to normal operating
temperature. Ensure all accessories are off. Shut engine off. Remove
air duct at throttle body.

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2) Disconnect vacuum line at PCV valve located in valve
cover. Install .185" fixed orifice Air Metering Fitting (6714) into
disconnected vacuum line in place of PCV valve.
3) Disconnect purge vacuum hose from passenger's side front
corner of throttle body, next to MAP sensor. Place cap on vacuum hose
fitting on throttle body.
4) Connect scan tool to Data Link Connector (DLC) located
below driver's side of instrument panel, near steering column. See
Fig. 1, 2 or 3.
5) Start engine and warm engine to normal operating
temperature. Using scan tool manufacturer's instructions, select
SYSTEM TEST and then access the MINIMUM AIRFLOW display on scan tool.
When accessed, scan tool will count down to stabilize idle RPM and
display minimum airflow idle RPM. Minimum airflow idle RPM should be
500-900 RPM.
6) Shut engine off. If minimum airflow idle RPM is correct,
throttle body is okay. Go to next step. If minimum airflow idle RPM is
not within specification, using approved cleaner, clean throttle body
and recheck minimum airflow idle RPM. If correct minimum airflow idle
RPM cannot be obtained, replace throttle body. Go to next step.
7) Remove air metering fitting. Reinstall vacuum hoses as
necessary. Reinstall air duct on throttle body. Remove scan tool.
Ram Pickup 8.0L
Throttle body minimum airflow cannot be checked on this
application.
THROTTLE POSITION SENSOR
NOTE: Throttle Position (TP) sensor is nonadjustable. Use following\
procedure to check TP sensor calibration. For complete
testing of TP sensor and wiring circuit, see SELF-DIAGNOSTICS
- JEEP, TRUCKS & RWD VANS article.
Dakota, Ram Pickup, Ram Van & Ram Wagon
1) Remove components for access to electrical connector at TP
sensor mounted on throttle body. With electrical connector installed
on TP sensor, turn ignition on with engine off. DO NOT start engine.
2) Using digital volt-ohmmeter, measure voltage at center
terminal on electrical connector for TP sensor with throttle valve
closed (idle position). Voltage should be greater than .35 volt, but
less than .90 volt.
3) Slowly open throttle to full throttle and note voltage
reading. Voltage should smoothly increase to less than 4.50 volts.
Replace TP sensor if voltage is not within specification.

Page 173 of 1691

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

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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.

Page 186 of 1691

Requested WARM boot or User-Requested COLD boot. If DRB should display
any other error message, record entire display and contact
manufacturer.
2) If DRB does not power-up, check for loose cable
connections or a bad cable. Check vehicle battery voltage (data link
connector terminal No. 16). A minimum of 11 volts is required to
adequately power DRB.
3) If all connections are proper between DRB and vehicle or
other devices, and vehicle battery is fully charged, an inoperative
DRB may be result of faulty cable or vehicle wiring.
ENTERING ON-BOARD DIAGNOSTICS
1) Before entering on-board diagnostics, refer to
PRETEST INSPECTION & DIAGNOSTIC PROCEDURE . Connect DRB to data link
connector. Data link connector (DLC) is located under left side of
instrument panel, left of steering column.
NOTE: Read active DTCs with PAD switch in both ON and OFF
positions. Always turn ignition off before changing PAD
switch positions,
2) Turn ignition switch to ON position. Exit vehicle with
DRB. Using DRB, read and record active Diagnostic Trouble Code (DTC)
data. Read and record stored DTC data. If any DTCs (fault messages)
exist, perform appropriate test.
3) If PAD switch OFF indicator fails to illuminate when in
the OFF position, go to PAD SWITCH INDICATOR PROBLEMS . If PAD switch
OFF indicator illuminates when switch is in ON position or key
cylinder does not operate, replace PAD switch.
4) Air Bag Control Module (ACM) may report any of the
following DTCs or fault messages. If the following active or stored
codes are reported by DRB, replace ACM. See
AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION.
* ACM OUTPUT DRIVER CIRCUIT OPEN
* ACM ACCELEROMETER
* ACM INTERNAL DIAGNOSTIC CODE #1
* WARNING LAMP DRIVER ERROR
* FIRING CAPACITOR LOW
* LOGIC CAPACITOR LOW
* SAFING SENSOR SHORTED
If the following active codes are reported by DRB, go to the
appropriate procedure under DIAGNOSTIC TESTS.
* CLUSTER MESSAGE MISMATCH
* DRIVER SQUIB CIRCUIT OPEN
* DRIVER SQUIB CIRCUIT SHORTED
* DRIVER SQUIB CIRCUIT SHORTED TO BATTERY
* DRIVER SQUIB CIRCUIT SHORTED TO GROUND
* LOSS OF IGNITION RUN ONLY
* LOSS OF IGNITION RUN/START
* NO CLUSTER CCD MESSAGE
* NO CCD COMMUNICATION
* MISSING OR INVALID VIN
* PASSENGER SQUIB CIRCUIT OPEN
* PASSENGER SQUIB CIRCUIT SHORTED
* PASSENGER SQUIB CIRCUIT SHORTED TO BATTERY
* PASSENGER SQUIB CIRCUIT SHORTED TO GROUND
* SCTM FAILURE
* SCTM MESSAGE MISMATCH
* VIN MESSAGE MISMATCH

Page 192 of 1691

Fig. 16: Identifying Data Link Connector (DLC) Terminals
Courtesy of DaimlerChrysler Corp.

Page 208 of 1691

inspect it to ensure it is in good condition. Always focus on
circuit being tested. Dirt, water and corrosion, are most
common problems in connectors. Due to manufacturer changes in
wire colors, use terminal identification whenever possible.
1) Ensure ignition switch is in the RUN position. Disconnect
Powertrain Control Module (PCM) connectors. If DRB does not display
BUS SHORT TO BATTERY, to step 8). If DRB displays BUS SHORT TO
BATTERY, go to next step.
2) Disconnect instrument cluster connectors. If DRB does not
display BUS SHORT TO BATTERY, replace instrument cluster. If DRB
displays BUS SHORT TO BATTERY, go to next step.
3) Turn ignition off and wait 2 minutes before proceeding.
Disconnect air bag control module connector. Turn ignition on (engine
off). If DRB does not display SHORT TO BATTERY, replace ACM. If DRB
displays SHORT TO BATTERY, go to next step.
4) Disconnect Central Timer Module (CTM) 18-pin connector. I\
f
DRB does not display BUS SHORT TO BATTERY, replace CTM. If DRB
displays BUS SHORT TO BATTERY, go to next step.
5) Disconnect anti-lock brake controller. If DRB does not
display BUS SHORT TO BATTERY, replace anti-lock brake controller. If
DRB displays BUS SHORT TO BATTERY, go to next step.
6) Disconnect DRB from Data Link Connector (DLC). Using a
voltmeter, check voltage between ground and DLC connector terminal No.
3 (Violet/Brown wire). If voltage is more than 0.2 volt, repair short
in Violet/Brown wire. If voltage is less than 0.2 volt, go to next
step.
7) Using a voltmeter, check voltage between ground and DLC
connector terminal No. 11 (White/Black wire). If voltage is more than
0.2 volt, repair short in White/Black wire. If voltage is less than 0.
2 volt, replace DRB or DRB cable as necessary.
8) Turn ignition off. Using an ohmmeter, check resistance
between ground and PCM Black connector terminal A31 (Black/Tan wire).
If resistance is more than 10 ohms, repair open in Black/Tan wire). If
resistance is less than 10 ohms, go to next step.
9) Using an ohmmeter, check resistance between ground and PCM
Black connector terminal A32 (Black/Tan wire). If resistance is more
than 10 ohms, repair open in Black/Tan wire). If resistance is less
than 10 ohms, replace Powertrain Control Module (PCM).
NO RESPONSE FROM INSTRUMENT CLUSTER
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
after all repairs. Each time a connector is disconnected,
inspect it to ensure it is in good condition. Always focus on
circuit being tested. Dirt, water and corrosion, are most
common problems in connectors. Due to manufacturer changes in
wire colors, use terminal identification whenever possible.
1) Remove Instrument cluster. Using DRB, turn on INTERNAL BUS
BIAS under SYSTEM MONITORS CCD BUS VOLTAGE. Connect a jumper wire from
Black instrument cluster 10-pin connector "A" terminal No. 9
(White/Black wire) to ground. Observe CCD BUS voltage on DRB. If
voltage did not drop to about zero volt, repair open in White/Black
wire. If voltage drops to about zero volt, go to next step.
2) Leave internal DRB CCD BUS BIAS turned on. Connect a
jumper wire from ground to Black instrument cluster 10-pin connector
"A" terminal No. 10 (Violet/Brown wire). Go to next step.
3) Observe CCD BUS voltage on DRB. If voltage did not drop to
about zero volt, repair open in Violet/Brown wire. If voltage drops to
about zero volt, replace instrument cluster.

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