1999 DODGE RAM check engine
[x] Cancel search: check enginePage 390 of 1691
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
Page 397 of 1691
next step. If scan tool does not display brake pedal PRESSED and
RELEASED, go to NTC-1: BRAKE SWITCH SENSE.
4) Turn S/C on. On A/T models, move gear selector to Drive.
If scan tool displays park neutral switch D/R, go to next step. If
scan tool does not display park neutral switch D/R, go to FTC P1899:
PARK/NEUTRAL POSITION SWITCH STUCK IN PARK OR IN GEAR under DIAGNOSTIC
TESTS.
5) On all models, using scan tool, actuate S/C vent solenoid.
Using a 12-volt test light, backprobe S/C brake switch output circuit
at S/C servo connector terminal No. 3 (Dark Blue/Red wire). If test
light is illuminated and bright, go to next step. If test light is dim
or is not illuminated, go to NTC-1: BRAKE SWITCH SENSE.
6) Start engine and let idle for one minute. Turn engine off.
Turn ignition on (engine off). Using scan tool, actuate S/C servo
solenoids. If throttle opens and closes, go to NTC-2: CHECKING FOR
SPEED CONTROL DENIED MESSAGE. If throttle does not open and close,
inspect throttle cable and linkage. Check vacuum supply. See VACUUM
SUPPLY under COMPONENT TESTS. Repair as necessary. Perform TEST VER-4A
under VERIFICATION TESTS.
7) While observing scan tool, press CANCEL switch several
times. If scan tool displays PRESSED and RELEASED, go to next step. If
scan tool does not display PRESSED and RELEASED, replace CANCEL
switch. Perform TEST VER-4A under VERIFICATION TESTS.
8) Turn ignition off. Disconnect S/C servo connector. Using
an ohmmeter, check resistance of ground circuit at S/C servo connector
terminal No. 4 (Black wire). If resistance is 5 ohms or more, repair
open ground circuit. Perform TEST VER-4A under VERIFICATION TESTS. If
resistance is less than 5 ohms, go to next step.
9) Reconnect S/C servo connector. Turn ignition and S/C on.
While observing scan tool, press SET switch several times. If scan
tool displays PRESSED and RELEASED, go to next step. If scan tool does
not display PRESSED and RELEASED, replace SET switch. Perform TEST
VER-4A under VERIFICATION TESTS.
10) Turn ignition off. Disconnect S/C servo connector.
Inspect terminals. If any terminal is damaged, pushed out or miswired,
repair as necessary. Perform TEST VER-4A under VERIFICATION TESTS. If
terminals are okay, go to next step.
11) Disconnect S/C servo connector. Disconnect PCM
connectors. Inspect connectors. Clean or repair as necessary. Using an
ohmmeter, check resistance of S/C vacuum solenoid control circuit
between PCM connector C3, terminal No. 4 and S/C servo connector
terminal No. 1 (Tan/Red wire). If resistance is 5 ohms or more, repair\
open circuit. Perform TEST VER-4A under VERIFICATION TESTS. If
resistance is less than 5 ohms, go to next step.
12) Turn S/C on. While observing scan tool, press COAST
switch several times. If scan tool displays PRESSED and RELEASED, go
to next step. If scan tool does not display PRESSED and RELEASED,
replace COAST switch. Perform TEST VER-4A under VERIFICATION TESTS.
13) Using an ohmmeter, check resistance of S/C vent solenoid
control circuit between PCM connector C3, terminal No. 5 and S/C servo
connector terminal No. 2 (Light Green/Red wire). If resistance is 5
ohms or more, repair open circuit. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is less than 5 ohms, replace S/C
servo. Perform TEST VER-4A under VERIFICATION TESTS.
NTC-1: BRAKE SWITCH SENSE
Possible Causes:
* Ground circuit open.
* Defective brake switch.
* Brake switch sense circuit open or shorted.
* Defective PCM.
Page 398 of 1691
1) Turn ignition off. Disconnect brake switch connector.
Inspect connector. Clean or repair as necessary. Turn ignition on.
Using a voltmeter, measure voltage of brake switch sense circuit at
brake switch White/Pink wire. If voltage is more than 10 volts, go to
next step. If voltage is 10 volts or less, go to step 3).
2) Connect a jumper wire between ground and brake switch
connector White/Pink wire. Using scan tool, read brake switch input
status. If scan tool displays brake switch released, replace brake
switch. Perform TEST VER-4A under VERIFICATION TESTS. If scan tool
does not display brake switch released, repair open ground circuit.
Perform TEST VER-4A under VERIFICATION TESTS.
3) Disconnect PCM connectors. Inspect connectors. Clean or
repair as necessary. Using an ohmmeter, measure resistance between
ground and brake switch sense circuit at PCM connector C3, terminal
No. 24 (White/Pink wire). If resistance less than 5 ohms, repair short\
to ground. Perform TEST VER-4A under VERIFICATION TESTS. If resistance
is 5 ohms or more, go to next step.
4) Using an ohmmeter, measure resistance of brake switch
sense circuit between PCM connector C3, terminal No. 24 and brake
switch White/Pink wire. If resistance is 5 ohms or more, repair open
brake switch sense circuit. Perform TEST VER-4A under VERIFICATION
TESTS. If resistance is less than 5 ohms, replace PCM. Perform TEST
VER-4A under VERIFICATION TESTS.
NTC-2: CHECKING FOR SPEED CONTROL DENIED MESSAGE
At this time speed control switch and servo functions appear
to operate properly. Using scan tool, monitor speed control output
status. Road test vehicle at speeds more than 30 MPH. Attempt to set
speed control. See SCAN TOOL DENIED STATUS table. Items listed in
table will not allow speed control to set. The last or most recent
cause for speed control not to set is indicated by denied status.
Correct fault and recheck system operation.
SCAN TOOL DENIED STATUS
\
\
\
\
\
\
\
Denied Message Reason
\
\b \
\
\
\
\
\
ON/OFF PCM Does Not See An ON Signal From Switch
At PCM Terminal No. 41
\
\b \
\
\
\
\
\
SPEED Vehicle Speed As Seen By PCM Terminal
No. 66 Is Not Greater Than 36 MPH
\
\b \
\
\
\
\
\
RPM Engine RPM Is Excessively High
\
\b \
\
\
\
\
\
BRAKE Brake Switch Sense Circuit Is Open
Indicating That Brakes Are Applied
\
\b \
\
\
\
\
\
P/N Park/Neutral Switch Sense Circuit Is Grounded
Indicating That Transmission Is In Park Or Neutral
\
\b \
\
\
\
\
\
RPM/SPD PCM Senses Excessive Engine RPM
For A Given Vehicle Speed
\
\b \
\
\
\
\
\
SOL FLT PCM Senses A Servo Solenoid Circuit
Trouble Code That Is Maturing Or Set In Memory
\
\
\
\
\
\
\
\f
NTC-3: SPEED CONTROL ON/OFF SWITCH
Possible Causes:
Page 400 of 1691
under VERIFICATION TESTS. If voltage is one volt or more, go to next
step.
2) Turn ignition off. Using an ohmmeter, check resistance of
RESUME/ACCEL switch ground circuit at RESUME/ACCEL switch connector.
If resistance is 5 ohms or more, repair open ground circuit. Perform
TEST VER-4A under VERIFICATION TESTS. If resistance is less than 5
ohms, repair open S/C switch signal circuit. Perform TEST VER-4A under
VERIFICATION TESTS.
VERIFICATION TESTS
TEST VER-4A
NOTE: If PCM has been replaced and correct VIN and mileage have not
been programmed, a FTC will be set in ABS and air bag
modules. If vehicle is equipped with a Sentry Key Immobilizer
Module (SKIM), sentry key data must be updated to enable
starting. See COMPUTER RELEARN PROCEDURES article in GENERAL
INFORMATION.
1) If vehicle is not equipped with a diesel engine, go to
next step. If vehicle is equipped with a diesel engine, and PCM has
been disconnected or replaced, battery has been disconnected, or
Accelerator Pedal Position Sensor (APPS) has been disconnected or
replaced, APPS calibration must be programmed into PCM (diesel only).
Turn ignition on. Slowly press accelerator pedal to floor and slowly
release. DO NOT attempt to adjust screws or disassemble APPS. Go to
next step.
2) On all engines, if vehicle is equipped with ABS or air
bag, enter correct VIN and mileage in PCM. Erase DTCs in ABS and air
bag modules. Inspect vehicle to ensure all engine and speed control
system components are connected. Reassemble and reconnect components
as necessary. Using scan tool, erase DTCs from PCM.
3) Road test vehicle at a speed greater than 35 MPH. Turn S/C
switch on. Press and release SET button. If S/C does not engage,
repair is not complete. Check for related TSBs and return to TROUBLE
SHOOTING, if necessary. If speed control engages, go to next step
4) Quickly depress and release RESUME/ACCEL switch. If
vehicle speed increases by 2 MPH, go to next step. If vehicle speed
does not increase by 2 MPH, repair is not complete. Check for related
TSBs and return to TROUBLE SHOOTING, if necessary.
5) Press and hold COAST switch. Vehicle speed should
decrease. If vehicle speed decreases, go to next step. If vehicle
speed does not decrease, repair is not complete. Check for related
TSBs and return to TROUBLE SHOOTING, if necessary.
6) Using caution, depress and release brake pedal. If S/C
disengages, go to next step. If S/C does not disengage, repair is not
complete. Check for related TSBs and return to TROUBLE SHOOTING, if
necessary.
7) Bring vehicle speed to 35 MPH. Depress speed control
RESUME/ACCEL switch. If vehicle resumes to previously set speed, go to
next step. If vehicle does not resume to previously set speed, repair
is not complete. Check for related TSBs and return to TROUBLE
SHOOTING, if necessary.
8) Hold down SET switch. Vehicle speed should decrease. If
vehicle speed decreases, go to next step. If vehicle speed did not
decrease, repair is not complete. Check for related TSBs and return to
TROUBLE SHOOTING, if necessary.
9) Ensure vehicle speed is more than 35 MPH and release SET
switch. If vehicle sets a new speed, go to next step. If vehicle did
not set a new speed, repair is not complete. Check for related TSBs
and return to TROUBLE SHOOTING, if necessary.
Page 401 of 1691
10) Depress and release CANCEL switch. If S/C disengages, go
to next step. If S/C did not disengage, repair is not complete. Check
for related TSBs and return to TROUBLE SHOOTING, if necessary.
11) Ensure vehicle speed is greater than 35 MPH. Engage speed
control. Turn S/C on/off switch to OFF position. If speed control
disengages, system is operating correctly. Repair is complete. If
speed control does not disengage, repair is not complete. Check for
related TSBs and return to TROUBLE SHOOTING, if necessary.
TEST VER-5A
NOTE: If PCM has been replaced and correct VIN and mileage have not
been programmed, a FTC will be set in ABS and air bag
modules. If vehicle is equipped with a Sentry Key Immobilizer
Module (SKIM), sentry key data must be updated to enable
starting. See COMPUTER RELEARN PROCEDURES article in GENERAL
INFORMATION.
1) If vehicle is not equipped with a diesel engine, go to
next step. If vehicle is equipped with a diesel engine, and PCM has
been disconnected or replaced, battery has been disconnected, or
Accelerator Pedal Position Sensor (APPS) has been disconnected or
replaced, APPS calibration must be programmed into PCM (diesel only).
Turn ignition on. Slowly press accelerator pedal to floor and slowly
release. DO NOT attempt to adjust screws or disassemble APPS. Go to
next step.
2) On all engines, if vehicle is equipped with ABS or air
bag, enter correct VIN and mileage in PCM. Erase DTCs in ABS and air
bag modules. Inspect vehicle to ensure all engine and speed control
system components are connected.
3) If there are any DTCs that have not been repaired, go to
SELF-DIAGNOSTIC SYSTEM. After all DTCs have been repaired, run
appropriate monitor for previously repaired FTC.
4) Connect scan tool to DLC. Ensure fuel tank is at least 1/4
full. Turn off all accessories. Allow PCM to run appropriate monitor
and increment appropriate good trip. Enabling conditions must be met
before monitor will run.
5) Using scan tool, monitor pretest enabling conditions until
all conditions have been met. Once enabling conditions have been met,
monitor appropriate monitor.
6) If repaired FTC has reset or was seen in monitor while on
road test, repair is not complete. Check for TSBs or flash updates and
return to TROUBLE SHOOTING.
7) If appropriate monitor ran, good trip counter incremented
and no DTCs have been set, repair is complete.
REMOVAL & INSTALLATION
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.
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.
BRAKE SWITCH
Removal
Page 421 of 1691
(1) - Approximate drive axle capacity listed. Lubricant level should
be within 1/2" below bottom of oil filler hole in axle housing
cover.
( 2) - Add container of Mopar Gear Oil Friction Modifier when
refilling.
\
\
\
\
\
\
\
FLUID TYPE
Use SAE 80W-90 or SAE 90W hypoid gear lubricant with MIL-L-
2105-B and API GL-5 ratings. Also add a container of Mopar Gear Oil
Friction Modifier when refilling.
FLUID DRAIN & REFILL
1) With lubricant of rear axle assembly at normal operating
temperature, raise and support vehicle so rear wheels are free to
rotate. Clean around axle housing cover. Loosen axle housing cover
bolts. Drain lubricant from axle housing. Remove bolts and axle
housing cover.
2) Position differential so hole in differential case faces
down. Wipe all accessible areas of axle housing. Ensure sealing
surfaces on axle housing and cover are clean. Apply a 1/4" thick bead
of silicone sealant on inside of bolt holes and along sealing surfaces
on axle housing cover.
3) Install axle housing cover, axle identification tag and
retaining bolts. Tighten bolts to 30 ft. lbs. (41 N.m). Remove oil
filler plug. Add a container of Mopar Gear Oil Friction Modifier. Fill
axle with gear lube. Install oil filler plug. Lower vehicle.
TROUBLE SHOOTING
DIFFERENTIAL NOISE
1) Ensure differential lubricant is at normal operating
temperature. Road test vehicle. Note if differential noise exists in
turns, but not during straight-ahead driving. Probable cause is
incorrect or insufficient rear axle lubricant or additive.
2) Drain and refill rear axle. See FLUID DRAIN & REFILL under
LUBRICATION. Road test vehicle and note if noise still exists, it may
be necessary to disassemble rear axle so differential can be repaired.
See RBI FULL-FLOATING AXLES article for removal of differential case.
TESTING
NOTE: Power-Lok differential can be tested without removing
differential carrier from axle housing. Either test can be
used to check drive axle.
TEST I
1) Place blocks under both front wheels. Ensure engine is off
and transmission is in Neutral. Release parking brake. Raise one rear
wheel until it is completely clear of the floor. Remove wheel. Install
Adapter (6790) to wheel studs, and tighten securely.
2) Using torque wrench on adapter, rotate axle, and record
torque required. Repeat procedure for remaining rear wheel position.
If rotational torque for either rear wheel is less than 30 ft. lbs.
(41 N.m) or greater than 200 ft. lbs. (271 N.m), Power-Lok unit must\
be replaced or repaired.
Page 458 of 1691
Apply multipurpose lubricant (NLGI grade 2 EP) to "U" joints
and slip joint fittings.
INSPECTION
Abnormal vibration and noise can come from many driveline
sources. Drive shaft vibration/noise increases with vehicle speed
(MPH). A vibration that occurs within a specific speed is not caused
by drive shaft imbalance. Before overhauling driveline, check for
other causes/sources of possible vibration/noise.
TIRES & WHEELS
Check tire inflation and wheel balance. Check for foreign
objects in tread, damaged tread, mismatched tread patterns or
incorrect tire sizes. Check for bent wheels.
CENTER BEARING
Tighten drive shaft center bearing mounting bolts. If bearing
insulator is deteriorated or oil-soaked, or drive shaft can be moved
up/down in support, replace center bearing support assembly.
ENGINE & TRANSMISSION MOUNTS
Tighten mounting bolts. If rubber mounts are deteriorated or
broken, replace as needed.
DRIVE SHAFT(S)
Check drive shaft(s) for missing weights, broken welds, or
for dents affecting balance. Check for undercoating, mud, snow/ice on
drive shaft(s). Clean shafts thoroughly and test drive.
"U" JOINTS
Check for foreign material lodged in joints and flange/yokes.
Check for loose "U" joint-to-flange mounting bolts. Check for worn "U"
joint needle bearings. Check for Reddish-Brown rust-dust around "U"
joint caps. Replace "U" joints if necessary.
ADJUSTMENTS
CHECKING DRIVE SHAFT PHASING
One-Piece Drive Shafts
1) Ensure "U" joint flanges on either end of drive shaft are
in same plane. See Fig. 2. Drive shafts with slip joints between yokes
often have arrows to aid in alignment. If yokes are not in same plane,
disassemble slip joint from drive shaft splines. Install slip joint
back onto drive shaft splines, aligning "U" joint yokes. Test drive.
2) Single tube type drive shaft has slip joint on outside of
"U" joint yoke (at transmission end). If one-piece tube type drive
shaft yokes are out of alignment, the drive shaft is torque-twisted.
Drive shaft must be replaced.
Page 460 of 1691
1) On drive shafts greater than 30" in length, measure runout
3" from transmission flange/yoke, center bearing yoke and pinion
flange using dial indicator. Maximum runout for Ram Pickup is .030" (.
76 mm) at front and rear end of drive shaft and .035" (.89 mm) at
center of drive shaft. Maximum runout for all other models is .010" (.
25 mm) at front and rear end of drive shaft and .015" (.38 mm) at
center of drive shaft.
2) For drive shafts less than 30" in length, maximum runout
for Pickup is .030" (.76 mm). Maximum runout for all other models is .\
020" (.51 mm). Replace drive shaft if maximum runout is exceeded.
BALANCING DRIVE SHAFT
1) Perform following procedure only after inspecting all
other possible causes of vibration. See INSPECTION. Drive shaft
imbalance may often be cured by disconnecting shaft, rotating it 180
degrees and reconnecting shaft to flange. Test drive to check results.
NOTE: DO NOT run engine for prolonged periods without forced
airflow across radiator. Engine or transmission may
overheat.
2) To balance drive shaft(s), begin by raising rear wheels
off ground and turning drive shaft with engine. Balance testing may be
done by marking drive shaft in 4 positions, 90 degrees apart around
shaft. Place marks about 6" forward of rear flange/yoke weld. Number
marks 1-4.
3) Install large diameter screw-type hose clamp around drive
shaft so clamp's head is in No. 1 position. Spin drive shaft with
engine and note vibrations. If there is little or no change in
vibration intensity, move clamp head to No. 2 position, and repeat
test.
4) Continue procedure until vibration is at lowest level. If
no difference is noted with clamp head moved to all 4 positions,
vibrations may not be due to drive shaft imbalance.
5) If vibration decreases but is not completely eliminated,
place a second clamp at same position, and repeat test. Combined
weight of both clamps in one position may increase vibration. If so,
rotate clamps 1/2" apart, above and below lowest vibration level
position, and repeat test.
6) Continue to rotate clamps, as necessary, until vibration
is at lowest point. If vibration can be eliminated or reduced to
acceptable level, bend back slack end of clamp so screw cannot loosen.
If vibration level is still unacceptable, leave rear clamp(s) in
place, and repeat procedure at front end of drive shaft. Road test
vehicle. On 4WD models, perform procedure on each shaft.
CHECKING VERTICAL ANGLE
One-Piece Drive Shafts
1) Raise and support vehicle so rear wheels can be rotated.
Rotate drive shaft so a pinion flange bearing cap faces downward.
Attach Inclinometer (C-4224) magnet to bearing cap, and measure drive
shaft vertical angle. See Fig. 4. Remove inclinometer.
2) Rotate drive shaft 90 degrees until drive shaft rear yoke
bearing cap faces downward. Attach inclinometer magnet to bearing cap,
and measure drive shaft vertical angle. Difference between 2 measured
angles is drive shaft rear angle. See Fig. 5. Remove inclinometer.
3) Rotate drive shaft until a slip joint yoke bearing cap
faces downward. Attach inclinometer magnet to bearing cap, and note
angle. Remove inclinometer. Rotate drive shaft 90 degrees until drive
shaft front yoke bearing cap faces downward. Attach inclinometer
magnet to bearing cap, and note angle. Remove inclinometer.