1999 DODGE NEON engine

SPEED CONTROL SWITCHES
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provide
inputs to the PCM for ON, OFF, RESUME, ACCEL-
ERATE, SET, DECEL and CANCEL modes. Refer to
the owner's manual for more information on speed
control switch functions and setting procedures.When speed control is selected by depressing the
ON switch, the PCM allows a set speed to be stored
in RAM for speed control. To store a set speed,
depress the SET switch while the vehicle is moving
at a speed between 30 and 85 mph. In order for the
speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
NOTE: Depressing the OFF switch or turning off
the ignition switch will erase the set speed stored
in the PCM.
For added safety,the speed control system is pro-
grammed to disengaged for any of the following con-
ditions:
²An indication of Park or Neutral
²An rpm increase without a VSS signal increase
(indicates that the clutch has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The VSS signal increases at a rate of 10 mph
per second (indicates that the co-efficient of friction
between the road surface and tires is extremely low)
²The VSS signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
²If the actual speed is not within 20 mph of the
set speed
The previous disengagement conditions are pro-
grammed for added safety.
Once the speed control has been disengaged,
depressing the ACCEL switch when speed is greater
than 25 mph restores the vehicle to the target speed
that was stored in the PCM.
NOTE: Depressing the OFF switch will erase the
set speed stored in the PCM's RAM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the ACCEL
switch. The new target speed is stored in the PCM
when the ACCEL is released. The PCM also has a
9tap-up9feature in which vehicle speed increases at a
rate of approximately 2 mph for each momentary
switch activation of the ACCEL switch. The PCM
also provides a means to decelerate without disen-
gaging speed control. To decelerate from an existing
recorded target speed, depress and hold the COAST
switch until the desired speed is reached, then
release the switch.
Fig. 2 MTX Speed Control System
Fig. 3 ATX Speed Control System
8H - 2 VEHICLE SPEED CONTROL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

The individual switches cannot be repaired. If one
switch fails, the entire switch module must be
replaced.
STOP LAMP SWITCH
Vehicles equipped with the speed control option use
a dual function stop lamp switch. The switch is
mounted on the brake pedal mounting bracket under
the instrument panel. The PCM monitors the state of
the dual function stop lamp switch. Refer to Group 5,
Brakes for more information on stop lamp switch ser-
vice and adjustment procedures.
SERVO CABLE
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage. This cable causes the
throttle control linkage to open or close the throttle
valve in response to movement of the vacuum servo
diaphragm.
POWERTRAIN CONTROL MODULE
The speed control electronic control circuitry is
integrated into the Powertrain Control Module
(PCM). The PCM is located in the engine compart-
ment. The PCM speed control functions are moni-
tored by the On-Board Diagnostics (OBD). All OBD-
sensed systems are monitored by the PCM. Each
monitored circuit is assigned a Diagnostic Trouble
Code (DTC). The PCM will store a DTC in electronic
memory for any failure it detects. See On-Board
Diagnostic Tests in this group for more information.
The PCM cannot be repaired and must be replaced if
faulty.
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE ORIGINAL VEHICLES MILEAGE. IF THIS
STEP IS NOT DONE A DIAGNOSTIC TROUBLE
CODE (DTC) MAY BE SET.
VACUUM RESERVOIR
The reservoir contains a one-way check valve to
trap engine vacuum in the reservoir. When engine
vacuum drops, as in climbing a grade while driving,
the reservoir supplies the vacuum needed to main-
tain proper speed control operation. The vacuum res-
ervoir cannot be repaired and must be replaced if
faulty.
VEHICLE SPEED AND DISTANCE
The 4 speed automatic Transmission Control Mod-
ule (TCM) supplies the speed input to the PCM. The
PCM determines acceleration rates. The speed con-
trol software in the PCM uses vehicle speed and
acceleration to control to the set speed.Vehicles with a 3 speed automatic or manual trans-
mission have a vehicle speed sensor (VSS) mounted
to an adapter near the transmission output shaft.
The sensor is driven through the adapter by a speed-
ometer pinion gear. The VSS pulse signal is moni-
tored by the PCM to determine vehicle speed and to
maintain speed control set speed. Refer to the appro-
priate Powertrain Diagnostic Procedures manual for
diagnosis and testing of this component. Refer to
group 14, Fuel System for Removal/Installation
DIAGNOSIS AND TESTING
ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-
ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Group 8E,
Instrument Panel and Gauges for speedometer diag-
nosis.
If a road test verifies a surge following a set and
the speedometer operates properly see ªOvershoot/
Undershoot on speed control setº.
If a road test verifies an inoperative system, and
the speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose or corroded electrical connections at the
servo. Corrosion should be removed from electrical
terminals and a light coating of Mopar Multipurpose
Grease, or equivalent, applied.
²Leaking vacuum reservoir.
²Loose or leaking vacuum hoses or connections.
²Defective one-way vacuum check valve.
²Secure attachment at both ends of the speed
control servo cable.
²Smooth operation of throttle linkage and throttle
body air valve.
²Conduct electrical test at PCM.
²Failed speed control servo. Do the servo vacuum
test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
PLVEHICLE SPEED CONTROL SYSTEM 8H - 3
DESCRIPTION AND OPERATION (Continued)

CHECKING FOR DIAGNOSTIC CODES
When trying to verify a speed control system elec-
tronic malfunction: Connect a DRB scan tool if avail-
able to the data link connector. The connector is
located at left side of the steering column, and at
lower edge of the panel.
(1) A speed control malfunction may occur without
a diagnostic code being indicated.
Refer to Group 25, for further information and use-
age of the DRB scan tool and a more complete list of
Diagnostic Trouble Code.
SPEED CONTROL SLOWS DOWN BY ITSELF
Test vehicle speed sensor, refer to group 8E. If sen-
sor fails replace sensor, if it passes perform the fol-
lowing test:
(1) Perform the speed control switch test on the
DECEL switch, if it fails replace switch.
(2) If the switch passes, conduct the vacuum sup-
ply test.
(3) If it passes, conduct the servo vacuum test. If it
fails replace servo.
(4) If continuity, replace the PCM.
SPEED CONTROL ELECTRICAL TEST
Electronic speed control systems may be tested
using two different methods. One involves use of aDRB. If this test method is desired, refer to the Pow-
ertrain Diagnostic Test Procedures for charging and
speed control system manual.
The other test method uses a volt/ohm meter. The
volt/ohm meter method is described in the following
tests.
If any information is needed concerning wiring,
refer to Group 8W, Wiring Diagrams (Fig. 4).
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals, or seals. If
these components are damaged, intermittent or
complete system failure may occur.
When electrical connections are removed, corrosion
should be removed from electrical terminals and a
light coating of Mopar Multi-Purpose Grease, or
equivalent, applied. Inspect connectors for damage
terminals.
A poor connection can cause a complete or inter-
mittent malfunction and is also the only connection
in the circuit, that can not be tested. For this reason,
a loose connection may be misdiagnosed as a compo-
nent malfunction.
SPEED CONTROL DIAGNOSTIC TROUBLE CODES
Hex Code DRB Scan Tool Display Description of Diagnostic Trouble Code
23No Vehicle Speed Sensor
SignalNo vehicle distance (speed) sensor signal detected during
road load conditions.
OFSpeed Control Solenoid
CircuitsAn open or shorted condition detected in the Speed Control
vacuum or vent solenoid circuits.
56MUX S/C Switch High Speed Control switch input above the maximum acceptable
voltage.
57MUX S/C Switch Low Speed Control switch input below the minimum acceptable
voltage.
52S/C Power Relay Or 12V
Driver CircuitMalfunction detected with power feed to speed control servo
solnoids.
Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
8H - 4 VEHICLE SPEED CONTROL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

OVERSHOOT/UNDERSHOOT FOLLOWING SPEED
CONTROL SET
If the operator repeatedly presses and releases the
set button with their foot off of the accelerator (a ªlift
foot setº to begin speed control operation), the vehicle
may accelerate and exceed the desired set speed by
up to 5 MPH (8 km/h) and then decelerate to less
than the desired set speed before finally achieving
the desired set speed.
The Speed Control has an adaptive strategy that
compensates for vehicle-to-vehicle variations in speed
control cable lengths. When the speed control is set
with the vehicle operators foot off of the accelerator
pedal, the speed control thinks there is excessive
speed control cable slack and adapts. If the lift foot
sets are continually used, the speed control over-
shoot/undershoot condition will develop.
To ªunlearnº the overshoot/undershoot condition,
the vehicle operator has to press and release the set
button while maintaining the desired set speed with
the accelerator pedal (not decelerating or accelerat-
ing), and then turn the cruise control switch to the
OFF position (or press the CANCEL button if
equipped) after waiting 10 seconds. This procedure
must be performed approximately 10±15 times to
completely unlearn the overshoot/undershoot condi-
tion.
SERVO VACUUM TEST
(1) Turn ignition switch to the ON position with-
out starting engine. Activate speed control ON
switch.
(2) Disconnect the four-way electrical connector
and the vacuum harness at the servo (Fig. 5).
(3) Connect a jumper wire from Pin 3 of the servo
to Pin 3 of the wire connector.
(4) Ground Pins 2 and 4 in the servo. Do not con-
nect pin 1.
(5) Connect a hand held vacuum pump to the vac-
uum nipple and apply 10 - 15 inches of vacuum.
(6) If servo pulls cable, replace servo.
(7) Ground Pin 1 on servo.
(8) Check that the throttle cable pulls in and holds
as long as the vacuum pump is connected. After one
minute, check if cable is still holding. If cable does
not hold replace the servo.
(9) Disconnect jumper from pin 3. Cable should
return to rest position. If not, replace servo.
(10) Connect 4 way electrical connector and vac-
uum harness to servo.
SPEED CONTROL SWITCH TEST
Refer to the appropriate Powertrain Diagnostic
Manual for switch test valves.
STOP LAMP SWITCH TEST
(1) Remove the stop lamp switch refer to Stop
Switch Removal/Installation in this section. Discon-
nect connector from stop lamp switch (Fig. 6). Using
an ohmmeter, switch continuity may be checked as
follows:
(2) With switch plunger released, there should be
continuity between Pin 5 and Pin 6.
(3) With switch plunger depressed, there should be
continuity:
²Between Pin 1 and Pin 2.
²Between Pin 3 and Pin 4.
(4) If the above results are not obtained, the stop
lamp switch is defective or out of adjustment.
Fig. 5 Servo Harness Connector
Fig. 6 Stop Lamp Wiring
8H - 6 VEHICLE SPEED CONTROL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

(c) If continuity is OK between cavity 62 and
cavity 1, repair open circuit between cavity 2 of the
stop lamp switch connector and ground.
(6) Using an ohmmeter, check continuity from cav-
ity 76 on PCM connector to ground with the trans-
mission in park or neutral. If no continuity, test TRS/
Park-Neutral switch and switch wiring
(7) Turn speed control and ignition switch OFF.
(8) Unplug the BLACK 40-way connector from the
Powertrain Control Module (PCM)
(9) Using an ohmmeter, check continuity from cav-
ity 3 of servo connector to cavity 5 on the PCM con-
nector.
(a) If continuity is OK, replace PCM. Check cir-
cuit for short to ground before replacing PCM.
(b) If no continuity, remove stop lamp switch
and conduct Stop Lamp Switch Test. If test fails,
adjust or replace as necessary.
(c) If switch passes, measure continuity from
cavity 4 of stop lamp switch connector to cavity 3
of servo connector. Repair open circuit if necessary.
(d) If continuity is OK, measure continuity from
cavity 3 of stop lamp switch to cavity 5 of PCM
connector. Repair open circuit as necessary.
(e) Install PCM connectors onto PCM and speed
control servo connector to servo.
VACUUM SUPPLY TEST
(1) Disconnect vacuum hose at the servo and
install a vacuum gauge in the hose (Fig. 9).
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury. Shut off engine, the vacuum should continue to
hold 10 inches of mercury.
(3) If vacuum does not meet this requirement,
check and correct the following vacuum leaks in the
vacuum lines, check valve, vacuum reservoir or poor
engine performance.
VEHICLE SPEED SENSOR
For diagnosis and testing of the Vehicle Speed Sen-
sor (VSS), refer to the appropriate Powertrain Diag-
nostic Procedures service manual. Also refer to the
DRB scan tool.
REMOVAL AND INSTALLATION
SPEED CONTROL SERVO
REMOVAL
(1) Disconnect electrical connector from servo.
(2) Disconnect vacuum hoses from servo
(3) Remove 2 nuts retaining cable to servo.
(4) Remove hair pin holding cable to servo.
INSTALLATION
(1) Install hairpin to cable at servo.
(2) Install 2 nuts at cable to servo and servo
bracket, tighten to 7 N´m (60 ins. lbs.).
(3) Connect electrical connector to servo.
(4) Connect vacuum hose to servo
SPEED CONTROL SWITCH
The speed control switches are mounted in the
steering wheel and wired through the clock spring
device under the airbag module (Fig. 1).
WARNING: IF REMOVAL OF AIRBAG MODULE IS
NECESSARY, REFER TO GROUP 8M, RESTRAINT
SYSTEMS.
REMOVAL
(1) Turn off ignition.
(2) Remove two screws from side of each switch.
(3) Rock switch away from airbag and steering
wheel.
(4) Disconnect two-way electrical connector.
(5) Repeat for the other switch.
INSTALLATION
For installation reverse above procedures.
STOP LAMP SWITCH
REMOVAL
Remove the switch from the bracket by depressing
the brake pedal and rotating the switch in a counter-
clockwise direction approximately 30 degrees. Pull
the switch rearward and remove from bracket. Dis-
connect wiring harness connector.
INSTALLATION
Before installing the switch, reset the adjustable
switch plunger by pulling on the plunger head until
Fig. 9 Vacuum Gauge TestÐTypical
8H - 8 VEHICLE SPEED CONTROL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

HEADLAMP DIAGNOSIS
Always begin any diagnosis by testing all of the fuses and circuit breakers in the system. Refer to Group 8W,
Wiring Diagrams.
Conventional and halogen headlamps are interchangeable. It is recommended that they not be intermixed on
a given vehicle.
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
OR IGNITION TURNED
OFF2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system, refer to
Group 8A,
4. Battery has insufficient charge. 4. Test battery state-of-charge,
refer to Group 8A.
5. Battery is sulfated or shorted. 5. Load test battery, refer to Group 8A.
6. Poor lighting circuit Z1-ground. 6. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
7. Both headlamp bulbs defective. 7. Replace both headlamp bulbs.
HEADLAMP BULBS
BURN OUT1. Charging system output too high. 1. Test and repair charging system, refer to
Group 8A.
FREQUENTLY 2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices, refer to Group 8W.
HEADLAMPS ARE DIM
WITH ENGINE RUNNING1. Charging system output too low. 1. Test and repair charging system, refer to
Group 8A.
ABOVE IDLE* 2. Poor lighting circuit Z1-ground. 2. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp circuit.
4. Both headlamp bulbs defective. 4. Replace both headlamp bulbs.
HEADLAMPS FLASH
RANDOMLY1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
2. High resistance in headlamp
circuit.2. Test amperage draw of headlamp circuit.
Should not exceed 30 amps.
3. Faulty headlamps switch circuit
breaker.3. Replace headlamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and
splices, refer to Group 8W.
HEADLAMPS DO NOT
ILLUMINATE1. No voltage to headlamps. 1. Repair open headlamp circuit, refer to
Group 8W.
2. No Z1-ground at headlamps. 2. Repair circuit ground, refer to Group 8W.
3. Faulty headlamp switch. 3. Replace headlamp switch.
4. Faulty headlamp dimmer
(multi-function) switch.4. Replace multi-function switch.
5. Broken connector terminal or wire
splice in headlamp circuit.5. Repair connector terminal or wire splice.
1. Headlamps stay on with
key out (DRLM equipped
vehicles).1. Failed DRLM 1. Replace DRLM.
*Canada vehicles must have lamps ON.
8L - 2 LAMPSPL
DIAGNOSIS AND TESTING (Continued)

FOG LAMP
FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM WITH
ENGINE IDLING OR IGNITION
TURNED OFF.1. Loose or corroded battery cables. 1. Clean and secure battery cable
clamps and posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive
belt.
3. Charging system output too low. 3. Test and repair charging system.
Refer to Group 8A,
4. Battery has insufficient charge. 4. Test battery state-of -charge.
Refer to Group 8A.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Group
8A.
6. Poor lighting circuit Z1-ground. 6. Test for voltage drop across
Z1-ground locations. Refer to Group
8W.
FOG LAMP BULBS BURN OUT
FREQUENTLY1. Charging system output too high. 1. Test and repair charging system.
Refer to Group 8A.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors
and splices. Refer to Group 8W.
FOG LAMPS ARE DIM WITH
ENGINE RUNNING ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system.
Refer to Group 8A.
2. Poor lighting circuit Z1-ground. 2. Test for voltage drop across
Z1-ground locations. Refer to Group
8W.
3. High resistance in fog lamp
circuit.3. Test amperage draw of fog lamp
circuit.
FOG LAMPS FLASH RANDOMLY 1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across
Z1-ground locations. Refer to Group
8W.
2. High resistance in fog lamp
circuit.2. Test amperage draw of fog lamp
circuit.
3. Faulty fog lamp switch. 3. Replace fog lamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors
and splices. Refer to Group 8W.
FOG LAMPS DO NOT
ILLUMINATE1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Group 8W.
2. No Z1-ground at fog lamps. 2. Repair circuit ground. Refer to
Group 8W.
3. Faulty fog lamp switch. 3. Replace fog lamp switch.
4. Broken connector terminal or wire
splice in fog lamp circuit.4. Repair connector terminal or wire
splice.
5. Defective or burned out bulb. 5. Replace bulb.
PLLAMPS 8L - 3
DIAGNOSIS AND TESTING (Continued)

BULB APPLICATION
INDEX
page page
GENERAL INFORMATION
INTRODUCTION......................... 8
SPECIFICATIONS
EXTERIOR LAMPS........................ 8INTERIOR LAMPS........................ 8
GENERAL INFORMATION
INTRODUCTION
The following Bulb Application Tables list the lamp
title on the left side of the column and trade number
or part number on the right.
CAUTION: Do not use bulbs that have a higher
candle power than the bulb listed in the Bulb Appli-
cation Table. Damage to lamp can result.
Do not touch halogen bulbs with fingers or other
possibly oily surfaces. Bulb life will be reduced.
If a halogen bulb is contaminated with oil, clean
bulb with denatured alcohol or ammonia based sol-
vent.
SPECIFICATIONS
EXTERIOR LAMPS
LAMP BULB
Back-up...............................P21W
Center High Mounted Stop..................921
Front Fog Lamp..........................H-3
Headlamp...............................H-4
License Plate...........................W5W
Front Turn Signal.....................P21/5W
Tail/Stop.............................P21/5W
Rear Turn Signal.......................P21W
Rear Fog Lamp.........................P21W
Citylight...............................T4W
Side Repeater...........................T4W
INTERIOR LAMPS
LAMP BULB
ABS.................................PC194
Airbag...............................PC194
AshTray................................161
Brake Warning System Indicator...........PC194
Cigar Lighter............................203
Climate Controls.........................203
Console Gear Selector......................161
Dome Light..............................578
Glove Box...............................194
High Beam Indicator....................PC194
Ignition Key.............................161
Instrument Cluster.....................PC194
Rear Cargo..............................912
Seat Belt Indicator.......................PC74
Service Engine Soon....................PC194
Turn Signal Indicator....................PC194
Underhood..............................105
Visor Vanity.........................6501966
Volts Indicator..........................PC74
8L - 8 LAMPSPL