DODGE RAM 1999 Service Repair Manual

DTCs from ABS and SRS modules.
Updating Secret Key Data
Connect scan tool to Data Link Connector (DLC) below driver's\
side of instrument panel. Go to ENGINE, then MISC menu on scan tool.
Place the SKIM in SECURED ACCESS MODE by using the appropriate
Personal Identification Number (PIN) for this vehicle. PIN may be
obtained from the owner, vehicle's invoice, or from the manufacturer.
Select UPDATE THE SECRET KEY DATA. The data will be transferred from
Smart Key Immobilizer Module (SKIM) to the PCM.
NOTE: If 3 attempts are made to enter the SECURED ACCESS MODE using
the incorrect Personal Identification Number (PIN), the
SECURED ACCESS MODE will be locked out for one hour. To exit
this locked-out mode, leave ignition switch in the ON
position for one hour with all accessories turned off. It may
be necessary to monitor battery state and connect a battery
charger.
FWD CARS & FWD VANS
Transaxle Shift Quality Quick Learn Procedure (All FWD Cars
Except Avenger & Sebring Coupe, & All FWD Vans)
1) Transaxle shift quality quick learn procedure must be
performed to provide proper transaxle operation if any of the
following have been done:
* Vehicle battery was disconnected.
* Transaxle assembly was replaced.
* Transmission Control Module (TCM) was replaced.
* Solenoid assembly was replaced.
* Valve body was reconditioned or replaced.
2) Transaxle shift quality quick learn procedure must be
performed using Chrysler's Diagnostic Readout Box III (DRB-III) scan
tool. Following conditions must be met when performing transaxle shift
quality quick learn procedure:
* Brakes must be applied.
* Engine speed must be greater than 500 RPM.
* Throttle position sensor angle must be less than 3 degrees.
* Shift lever must remain in designated position until prompted
to shift to overdrive.
* Shift lever must remain in overdrive after the shift to
overdrive until scan tool indicates procedure is complete.
* Calculated oil temperature must be within 60-200
F
(16-93C).
3) Connect scan tool to Data Link Connector (DLC) below
driver's side of instrument panel. For DLC location, see appropriate
SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
4) Go to TRANSMISSION display on scan tool. Go to
MISCELLANEOUS display on scan tool. Select QUICK LEARN PROCEDURE
display on scan tool. Follow instructions displayed on scan tool to
perform transaxle shift quality quick learn procedure. Remove scan
tool.
Transaxle Shift Quality Quick Learn Procedure (Avenger &
Sebring Coupe)
1) Transaxle shift quality quick learn procedure must be
performed to provide proper transaxle operation after replacing or
overhauling transaxle. After transaxle work is completed, clear any
Diagnostic Trouble Codes (DTCs) as necessary. Connect Chrysler's

Diagnostic Readout Box III (DRB-III) scan tool to Data Link Connector
(DLC) below driver's side of instrument panel. For DLC location, see
appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
2) Select SPECIAL FUNCTION on scan tool. Set scan tool to
QUICK LEARN mode. Follow scan tool manufacturer's instructions to
perform transaxle shift quality quick learn procedure. Remove scan
tool.
Pinion Factor Procedure (All FWD Cars Except Avenger &
Sebring Coupe, & All FWD Vans)
1) Electronic pinion factor procedure must be performed to
provide proper speedometer operation if Transmission Control Module
(TCM) is replaced. If pinion factor procedure is not performed,
improper speedometer readings may exist or speedometer may not
operate. Pinion factor procedure must be performed using Chrysler's
Diagnostic Readout Box (DRB-III) scan tool.
2) Connect scan tool to Data Link Connector (DLC) below
driver's side of instrument panel. For DLC location, see appropriate
SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
3) Select TRANSMISSION system, MISCELLANEOUS functions, then
PINION FACTOR. Scan tool will now display tire size. If tire size is
incorrect, press ENTER key and select correct size. Press PAGE BACK
key to exit procedure.
Pinion Factor Procedure (Avenger & Sebring Coupe)
1) Transaxle uses rotation speed of output shaft to calculate
vehicle speed and cumulative distance travelled. Therefore, it is
necessary to input or update tire size into TCM memory after TCM has
been replaced or tire size has been changed.
2) Select SPECIAL FUNCTION on Chrysler's Diagnostic Readout
Box (DRB-III) scan tool. Set scan tool to PINION FACTOR mode. Input
tire size into TCM memory.
NOTE: New TCMs do not have tire size input into memory. TCM may
also be referred to as EATX module.

CRUIS E C O NTR O L S YSTE M

1999 D odge P ic ku p R 1500
1999 ACCESSORIES & EQUIPMENT
CHRY - Cruise Control Systems
Dakota, Durango, Ram Pickup, Ram Van & Ram Wagon
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 article in GENERAL INFORMATION
before disconnecting battery.
DESCRIPTION
The speed (cruise) control system is electronically
controlled and vacuum operated. The electronic control is integrated
into the Powertrain Control Module (PCM). System consists of the
following components: Powertrain Control Module (PCM), servo, speed
control switches, vacuum reservoir, vehicle speed sensor, speed
control relay and brake switch.
System controls are located on each side of steering wheel
air bag module and consist of ON/OFF, SET, RESUME/ACCEL, CANCEL AND
COAST buttons. System is designed to operate at speeds above 30 MPH.
OPERATION
SYSTEM CONTROLS
To Set Speed Control
Press ON/OFF button to turn speed control system on.
Accelerate to desired speed (minimum of 35 MPH) and press SET/COAST
button. Vehicle speed will be maintained.
NOTE: Speed control system will automatically disengage when
vehicle speed decreases to less than 35 MPH or increases to
more than 85 MPH.
To Disengage Speed Control
Press brake pedal. Press clutch pedal (M/T). Press CANCEL
button. Press ON/OFF button. If ON/OFF button is used, set speed will
be erased from memory.
To Resume Previous Speed
If set speed has not been erased from memory and vehicle
speed is more than 35 MPH, press RES/ACCEL button.
To Increase Speed
With speed control system on, increase set speed by rapidly
pressing and releasing RES/ACCEL button. Each pressing of button will
cause speed increase of 2 MPH. For example, pressing button 3 times
will increase speed by 6 MPH. To increase speed gradually, hold
RES/ACCEL button down until desired speed is reached. When button is
released, new set speed will be maintained.
To Decrease Speed
With speed control system on, decrease set speed by pressing
SET/COAST button. Vehicle speed will gradually decrease. Releasing
button will set a new speed as long as vehicle speed is still more
than 35 MPH.

COMPONENT LOCATIONS
COMPONENT LOCATIONS








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Component Location
ABS Control Module
Ram Pickup ....................... Left Side Of Engine Compartment
Ram Van/Wagon ...................................... Under Battery
Data Link Connector (DLC) ...... Lower Left Side Of Instrument Panel\
Output Shaft Speed Sensor (OSS) .......... Left Side Of Transmission\
Park/Neutral Position (PNP) Switch ....... Left Side Of Transmission\
Powertrain Control Module (PCM)
Dakota & Durango ............... Right Front Of Engine Compartment
Ram Pickup ............... Right Rear Corner Of Engine Compartment
Ram Van/Wagon ..................... Under Hood Next To Wiper Motor
Vehicle Speed Sensor (VSS) ........ On Transmission Or Transfer Case\
Extension Housing









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TROUBLE SHOOTING
ROAD TEST
Perform a road test to verify speed control malfunctions.
Ensure speedometer operation is smooth without flutter at all speeds.
Speedometer fluttering may cause surging in speed control system. For
speedometer diagnosis, see appropriate INSTRUMENT PANELS article. If
road test verifies a surge following speed control set and speedometer
operates smoothly, see OVERSHOOT/UNDERSHOOT FOLLOWING SPEED CONTROL
SET.
If road test verifies an inoperative system, and speedometer
operates smoothly, check for:
* Diagnostic Trouble Codes (DTCs). See SELF-DIAGNOSTIC
SYSTEM.
* Misadjusted brake switch. See BRAKE SWITCH under REMOVAL &
INSTALLATION.
* Poor electrical connections at servo.
* Leaking vacuum reservoir, check valve, hoses or connections.
See VACUUM SUPPLY under COMPONENT TESTS.
* Secure attachments of S/C servo cable.
* Smooth operation of throttle linkage.
* Defective PCM or wiring.
* Defective servo. See SPEED CONTROL SERVO under COMPONENT
TESTS.
To verify a speed control electronic malfunction, use scan
tool to check for DTCs. See SELF-DIAGNOSTIC SYSTEM. A speed control
malfunction may occur without setting a FTC. If no DTCs are stored, go
to CHECKING SPEED CONTROL OPERATION under SYSTEM TESTS.
OVERSHOOT/UNDERSHOOT FOLLOWING SPEED CONTROL SET
If operator repeatedly presses and releases set button with
their foot off accelerator (lift foot set) to begin speed control
operation, vehicle may accelerate and exceed desired set speed by 5
MPH and then decelerate to less than desired set speed before
achieving desired set speed.
Speed Control (S/C) has as adaptive strategy that compensates\
for variations in S/C cable lengths. When S/C is set with vehicle

operator's foot off accelerator pedal, S/C compensates for excessive
S/C cable slack. If lift foot sets are continually used, speed control
overshoot/undershoot condition will develop.
To "unlearn" overshoot/undershoot condition, operator must
press and release set button while maintaining desired speed with
accelerator pedal, then turn S/C switch to OFF position after waiting
10 seconds. This procedure must be repeated 10-15 times to completely
unlearn overshoot/undershoot condition.
COMPONENT TESTS
WARNING: Vehicle is equipped with an air bag. Air bag must be
deactivated before servicing speed control components on or
around steering column. See appropriate AIR BAG RESTRAINT
SYSTEMS article.
NOTE: For component locations, See COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
BRAKE SWITCH
Disconnect brake switch 6-pin connector. Using an ohmmeter,
check for continuity at brake switch. See Fig. 1. If continuity is not
as specified in BRAKE SWITCH CONTINUITY table, check brake switch
adjustment. See BRAKE SWITCH under REMOVAL & INSTALLATION. If brake
switch adjustment is okay, replace defective brake switch.
BRAKE SWITCH CONTINUITY








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Switch Plunger  Check Between  Continuity 


Position  Terminals  










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Released  5 & 6  Yes 










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Depressed  1 & 2  Yes 











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SPEED CONTROL SERVO
1) Start engine. Disconnect Speed Control (S/C) servo 4-pin
connector. Turn S/C on. Using a voltmeter, check voltage at S/C servo
connector terminal No. 3 (Dark Blue/Red wire). Battery voltage should
exist when brake pedal is not depressed. If battery voltage exists, go
to next step. If battery voltage does not exist, check circuit between
brake switch and S/C servo. See WIRING DIAGRAMS.
2) Connect a jumper wire between S/C servo pin No. 3 and S/C
servo connector terminal No. 3. Check voltage at S/C servo pins No. 1,
2 and 4. If battery voltage does not exist, replace S/C servo. If
battery voltage exists, go to next step.
3) Turn ignition off. Check for continuity between S/C servo
connector terminal No. 4 and ground. If continuity exists, test is
complete. If continuity does not exist, repair open ground circuit as
necessary.
VACUUM SUPPLY
Gasoline Engines
1) Disconnect vacuum hose at speed control servo. Install
vacuum gauge to disconnected vacuum hose. Start engine and observe

gauge. Vacuum reading should be a minimum of 10 in. Hg. Turn engine
off. Vacuum should continue to hold at a minimum of 10 in. Hg.
2) If vacuum is not as specified, check for kinked or leaking
vacuum lines, defective check valve, defective vacuum reservoir or
poor engine performance. If no problems are found, check speed control
servo. See SPEED CONTROL SERVO.
Diesel Engines
1) Disconnect vacuum hose at speed control servo. Install
vacuum gauge to disconnected vacuum hose. Start engine and observe
gauge. Vacuum reading should be a minimum of 25 in. Hg. A vacuum
reservoir is not used on diesel vehicles.
2) If vacuum is not as specified, disconnect vacuum supply
hose from vacuum pump. Install vacuum gauge to vacuum pump. Start
engine and observe gauge. If vacuum reading is not 25 in. Hg or more,
replace vacuum pump. If vacuum reading 25 in. Hg or more, go to next
step.
3) Check all vacuum hoses to speed control servo, vacuum pump
and heater-A/C system for leaks. Check vacuum check valve for leaks
and proper operation. Vacuum check valve is located in vacuum hose
between speed control servo and vacuum pump. If no problems are found,
check speed control servo. See SPEED CONTROL SERVO.
CONNECTOR IDENTIFICATION
Fig. 1: Identifying Brake Switch Terminals
Courtesy of Chrysler Corp.

Fig. 2: Identifying Brake Switch Harness Connector Terminals
Courtesy of Chrysler Corp.
Fig. 3: Identifying Powertrain Control Module (PCM) Connector
Terminals
Courtesy of Chrysler Corp.

Fig. 4: Identifying Speed Control (S/C) Servo Connector Terminals
Courtesy of Chrysler Corp.
SELF-DIAGNOSTIC SYSTEM
WARNING: Vehicle is equipped with an air bag. Air bag must be
deactivated before servicing speed control components on or
around steering column. See AIR BAG RESTRAINT SYSTEMS -
TRUCKS article.
SERVICE PRECAUTIONS
Before proceeding with diagnosis, the following precautions
must be followed:
* When using Diagnostic Trouble Code (FTC) tests for diagnosis,
DO NOT skip any steps, or incorrect diagnosis may result.
Always perform indicated verification procedure after repairs are

made.
* When using a jumper wire, ensure either jumper wire or
circuit is fuse-protected.
* Before disconnecting connector from any control module,
ensure ignition is off before removing connector.
* When checking voltage or continuity at any control module,
probe connector for control module from pin side. DO NOT
backprobe connector or probe wires through insulation.
* DO NOT cause short circuits when performing electrical tests.
This will set additional Diagnostic Trouble Codes (DTCs),
making diagnosis of original problem more difficult.
* Use specified test equipment when performing electrical
tests.
RETRIEVING DIAGNOSTIC TROUBLE CODES
NOTE: Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB). If using a generic scan tool,
ensure it is OBD-II certified. A generic scan tool may not be
capable of performing all necessary test functions.
Ensure battery is fully charged. Turn ignition off. Connect
scan tool to Data Link Connector (DLC). DLC is located under left side\
of instrument panel. Turn ignition on. Using scan tool manufacturer's
instructions, record all DTCs displayed on scan tool. If ant DTCs are
retrieved, perform appropriate test under DIAGNOSTIC TESTS. Once all
repairs are made, clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES.
If no DTCs are retrieved and fault still exists, go to CHECKING SPEED
CONTROL OPERATION under SYSTEM TESTS.
CLEARING DIAGNOSTIC TROUBLE CODES
Ensure ignition is off. Connect scan tool to DLC. Turn
ignition on. Using screen prompts on scan tool, erase DTCs from PCM.
DIAGNOSTIC TESTS
FTC P0720: LOW OUTPUT SPEED SENSOR (OSS) RPM MORE THAN 15 MPH
FTC P0720 will set if output shaft speed is less than 60 RPM
for 2.6 seconds when vehicle speed is more than 15 MPH.
Possible Causes:
* Defective Output Speed Sensor (OSS).
* OSS signal circuit open or shorted.
* OSS ground circuit open or shorted.
* Park/Neutral Position (PNP) switch FTC present.
* Defective PNP switch.
* Defective PCM.
1) Turn ignition on. Using scan tool, read DTCs. If FTC
specific good trip is displayed and equal to zero, go to next step. If
FTC specific good trip is equal to more than zero, go to step 13).
2) If there are any Park/Neutral Position (PNP) switch DTCs,\
repair PNP switch FTC first. Perform TEST VER-5A under VERIFICATION
TESTS. If there are no PNP switch DTCs, go to next step.
3) Using scan tool, read PNP switch state. While observing
scan tool, shift transmission through all positions. If scan tool did
not display P/N and D/R in correct positions, repair PNP switch or
circuit as necessary. Perform TEST VER-5A under VERIFICATION TESTS. If

scan tool displayed P/N and D/R in correct positions, go to next step.
4) Raise drive wheels and support vehicle, allowing wheels to
spin. Using scan tool, erase DTCs. Start engine. Using scan tool, read
Output Speed Sensor (OSS). Shift transmission into first gear. While
observing scan tool, allow wheels to spin at a speed less than 15 MPH.
If scan tool displays OSS more than 60 RPM, go to next step. If scan
tool displays OSS 60 RPM or less, go to step 7).
5) While wheels are spinning, wiggle wiring between OSS and
PCM. If OSS reading dropped while wiggling, repair intermittent short
or open circuit. Perform TEST VER-5A under VERIFICATION TESTS. If OSS
reading did not drop, go to next step.
6) Using scan tool, erase DTCs. Road test vehicle. Read DTCs.
If FTC P0720 returns, replace PCM. Perform TEST VER-5A under
VERIFICATION TESTS. If FTC P0720 did not return, go to step 13).
7) Turn ignition off. Disconnect PCM. Inspect connectors.
Clean or repair as necessary. Using an ohmmeter, measure resistance
between ground and OSS signal circuit at PCM connector C2, terminal
No. 28 (Light Green/Black wire on Ram Pickup; Light Green/White wire
on all other models). If resistance is less than 5 ohms, repair short
to ground. Perform TEST VER-5A under VERIFICATION TESTS.
8) Using an ohmmeter, measure resistance between ground and
OSS ground circuit at PCM connector C2, terminal No. 25 (Dark
Blue/Black wire). If resistance is less than 5 ohms, repair short to
ground. Perform TEST VER-5A under VERIFICATION TESTS. If resistance is
5 ohms or more, go to next step.
9) Disconnect OSS. Using an ohmmeter, measure resistance
across OSS terminals. If resistance is not 300-1200 ohms, replace OSS.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is 300-
1200 ohms, go to next step.
10) Using an ohmmeter, measure resistance of OSS signal
circuit between PCM connector C2, terminal No. 28 and OSS connector
(Light Green/Black wire on Ram Pickup; Light Green/White wire on all
other models). If resistance is more than 5 ohms, repair open circuit.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is 5 ohms
or less, go to next step.
11) Using an ohmmeter, measure resistance of OSS ground
circuit between PCM connector C2, terminal No. 25 and OSS connector
(Dark Blue/Black wire). If resistance is more than 5 ohms, repair open\
circuit. Perform TEST VER-5A under VERIFICATION TESTS. If resistance
is 5 ohms or less, go to next step.
12) Reconnect OSS. Using an ohmmeter, measure resistance
between PCM connector C2, terminals No. 25 (Dark Blue/Black wire) and
No. 28 (Light Green/Black wire on Ram Pickup; Light Green/White wire
on all other models). If resistance is 300-1200 ohms, replace PCM.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is not
300-1200 ohms, go to next step.
13) Inspect wiring and connectors. repair as necessary.
Perform TEST VER-5A under VERIFICATION TESTS. If wiring and connectors
are okay, go to next step.
14) Conditions required to set FTC are not present at this
time. Check freeze frame data to determine conditions when FTC was
set. Raise drive wheels and support vehicle, allowing wheels to spin.
Using scan tool, read OSS. Shift transmission into first gear. While
observing scan tool, allow wheels to spin at a speed less than 15 MPH.
Wiggle wiring between OSS and PCM. If OSS reading dropped while
wiggling, repair intermittent short or open circuit. Perform TEST VER-
5A under VERIFICATION TESTS. If OSS reading did not drop, no problem
is indicated at this time.
FTC P1595: SPEED CONTROL SOLENOID CIRCUITS
Speed Control (S/C) solenoid circuits are monitored when
engine is running, S/C switch is on and battery voltage is more than