1999 DODGE RAM display

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

IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
1) Turn ignition on. Using scan tool, read S/C inputs. While
observing display, press S/C ON/OFF switch several times and leave on.
If scan tool displays S/C switch OFF and ON, go to next step. If scan
tool does not display OFF and ON, go to step 3).
2) Using scan tool, measure S/C switch voltage. While
observing display, wiggle wiring between S/C switch and PCM. If
voltage was more than 4.9 volts at any time during wiggling, repair
wiring as necessary. Perform TEST VER-4A under VERIFICATION TESTS. If
voltage was 4.9 volts or less during wiggling, test is complete.
3) Turn ignition off. Disconnect S/C ON/OFF switch. Inspect
connector. Clean or repair as necessary. Using an ohmmeter, measure
resistance of S/C switch ground circuit. 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.
4) Turn ignition on. Using a voltmeter, measure voltage on
S/C switch signal circuit. If voltage is more than 6 volts, repair
short to voltage. Perform TEST VER-4A under VERIFICATION TESTS. If
voltage is 6 volts or less, go to next step.
5) Turn ignition off. Disconnect PCM. Inspect connectors.
Clean or repair as necessary. Using an ohmmeter, measure resistance of
S/C switch signal circuit between ON/OFF switch connector and PCM
connector C3, terminal No. 32 (White/Light Green wire on Ram Van & Ram
Wagon; Red/Light Green wire on all other models). If resistance is
less than 5 ohms, go to next step. If resistance is 5 ohms or more, go
to step 7).
6) Using an ohmmeter, measure resistance across ON/OFF
switch. Resistance should be 20,300-20,700 ohms. If resistance is not
as specified, replace ON/OFF switch. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is as specified, replace PCM.
Perform TEST VER-4A under VERIFICATION TESTS.
7) Disconnect clockspring 5-pin connector. Clockspring 5-pin
connector is located behind lower steering column shroud. Inspect
connectors. Clean or repair as necessary. Using an ohmmeter, measure
resistance of S/C switch signal circuit between PCM connector C3,
terminal No. 32 and clockspring connector (White/Light Green wire on
Ram Van and Ram Wagon; Red/Light Green wire on all other models). 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
clockspring. See appropriate AIR BAG RESTRAINT SYSTEMS article.
Perform TEST VER-4A under VERIFICATION TESTS.
FTC P1597: SPEED CONTROL SWITCH ALWAYS LOW
FTC P1597 will set if Speed Control (S/C) switch voltage is
less than 0.39 volts for 2 minutes when ignition is on and battery
voltage is more than 10.4 volts.
Possible Causes:
* S/C ON/OFF switch defective.
* S/C RESUME/ACCEL switch defective.
* S/C switch signal circuit shorted to ground.
* Defective PCM.
* Defective clockspring.
NOTE: For component locations, see COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
1) Turn ignition on. Using scan tool, read S/C switch

* PNP switch defective.
* PNP switch sense circuit open or shorted.
* PNP switch stuck.
* PCM defective.
NOTE: For component locations, see COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
1) Turn ignition on. Using scan tool, read PNP switch state.
While observing scan tool, move gear selector between Park and
Reverse. If scan tool displays P/N and D/R, go to next step. If scan
tool does not display P/N and D/R, go to step 3).
2) Turn ignition off. Inspect wiring and connectors related
to PNP switch. Repair as necessary. Perform TEST VER-5A under
VERIFICATION TESTS. If wiring and connectors are okay, condition to
set FTC is not present at this time. Test is complete. Use freeze
frame data to determine conditions when FTC was set.
3) Turn ignition off. Disconnect PCM. Inspect connectors.
Clean or repair as necessary. Using an ohmmeter, check resistance
between ground and PNP switch sense circuit at PCM connector C1,
terminal No. 6 (Black/White wire). While observing ohmmeter, move gear\
selector from Park to Reverse and back to Park. If resistance switched
from less than 10 ohms to more than 10 ohms, replace PCM. Perform TEST
VER-5A under VERIFICATION TESTS. If resistance was less than 10 ohms
at all times, go to next step. If resistance was more than 10 ohms at
all times, go to step 5).
4) Disconnect PNP switch. Inspect connectors. Clean or repair
as necessary. Using an ohmmeter, check resistance between ground and
PNP switch sense circuit. 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, repair or replace stuck PNP switch.
Perform TEST VER-5A under VERIFICATION TESTS.
5) Using an ohmmeter, check resistance of PNP switch circuit
between PNP switch connector and PCM connector C1, terminal No. 6
(Black/White wire). If resistance is 5 ohms or more, repair open
circuit. Perform TEST VER-5A under VERIFICATION TESTS. If resistance
is less than 5 ohms, replace PNP switch. Perform TEST VER-5A under
VERIFICATION TESTS.
SYSTEM TESTS
NOTE: For component locations, See COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
CHECKING SPEED CONTROL OPERATION
NOTE: Perform this test only if there are no DTCs.
1) Turn ignition on. Using scan tool, monitor S/C switch
inputs. Press S/C ON/OFF switch several times. If scan tool displays
speed control switch on and off, go to next step. If scan tool does
not display speed control switch on and off, go to NTC-3: SPEED
CONTROL ON/OFF SWITCH.
2) While observing scan tool, press RESUME/ACCEL switch
several times. If scan tool displays RESUME/ACCEL switch PRESSED and
RELEASED, go to next step. If scan tool does not display PRESSED and
RELEASED, go to NTC-4: SPEED CONTROL RESUME/ACCEL SWITCH.
3) While observing scan tool, press brake pedal several
times. If scan tool displays brake pedal PRESSED and RELEASED, go to

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.

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



\









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\









\









\







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:


ELE C TR O STA TIC D IS C HAR G E W AR NIN G - B ASIC IN FO RM ATIO N

1999 D odge P ic ku p R 1500
GENERAL INFORMATION
Electrostatic Discharge (ESD) Warning - Basic Information
All Makes amd Models
* PLEASE READ THIS FIRST *
NOTE: This article is intended for general information purposes
only.
INTRODUCTION
All Electrostatic Discharge (ESD) sensitive components
contain solid state circuits (transistors, diodes, semiconductors)
that may become damaged when contacted with an electrostatic charge.
The following information applies to all ESD sensitive devices. The
ESD symbol shown in Fig. 1 may be used on schematics to indicate which
components are ESD sensitive. See Fig. 1. Although different
manufactures may display different symbols to represent ESD sensitive
devices, the handling and measuring precautions and procedures are the
same.
Fig. 1: Sample ESD Symbol
HANDLING STATIC-SENSITIVE CIRCUITS/DEVICES

If equipped, the EMR light (some models may use a reminder
flag) reminds vehicle operator that an emission system maintenance is
required. This indicator is activated after a predetermined
time/mileage.
When performing a smog check inspection, ensure EMR indicator
is not activated. On models using an EMR light, light should glow when
ignition switch is turned to ON position and should turn off when
engine is running.
If an EMR flag is present or an EMR light stays on with
engine running, fail vehicle and service or replace applicable
emission-related components. To reset an EMR indicator, refer to
appropriate MAINTENANCE REMINDER LIGHTS in the MAINTENANCE section.
MALFUNCTION INDICATOR LIGHT (MIL)
The Malfunction Indicator Light (MIL) is used to alert
vehicle operator that the computerized engine control system has
detected a malfunction (when it stays on all the time with engine
running). On some models, the MIL may also be used to display trouble
codes.
As a bulb and system check, malfunction indicator light will
glow when ignition switch is turned to ON position and engine is not
running. When engine is started, light should go out.


IN STR UM EN T P A N EL - A N ALO G

1999 D odge P ic ku p R 1500
1999 ACCESSORIES & EQUIPMENT
CHRY - Analog Instrument Panels
Ram Pickup, Ram Van & Ram Wagon
DESCRIPTION & OPERATION
INSTRUMENT CLUSTER
All instrument cluster gauges are air core magnetic type.
Tachometer is optional. All gauges use data transferred on Chrysler
Collision Detection (CCD) bus. Instrument cluster incorporates a
Vacuum Fluorescent Display (VFD) for odometer display.
Brake warning light illuminates when ignition is on and
parking brake is applied. Brake warning light also illuminates if
brake hydraulic system failure occurs during service brake
application. Brake warning light bulb test occurs when ignition switch
is in START position.
Oil pressure warning light illuminates when engine oil
pressure is not sufficient to open oil pressure sending unit switch.
Oil pressure warning light bulb test occurs with ignition switch in
RUN position.
All instrument clusters include these analog gauges:
* Coolant Temperature Gauge
* Fuel Gauge
* Oil Pressure Gauge
* Speedometer
* Voltmeter
Instrument clusters include these indicator lights, if
vehicle is equipped with appropriate option:
* Air Bag
* Anti-Lock Brake System (ABS)
* Brake Warning
* Check Gauges
* Cruise On
* Headlight High Beam
* Low Fuel
* Low Washer Fluid
* CHECK ENGINE
* Overdrive Off
* Rear Wheel Anti-Lock (RWAL)
* Seat Belt Reminder
* Security
* Transmission Oil Temperature (A/T)
* Turn Signal
* Upshift (M/T)
* 4WD
SELF-DIAGNOSTIC SYSTEM
WARNING: Vehicle is equipped with an air bag system. To prevent air
bag deployment, disconnect negative battery cable and wait at
least 2 minutes before servicing instrument cluster. See
appropriate AIR BAG RESTRAINT SYSTEMS article.
CAUTION: When battery is disconnected, vehicle computer and memory