2000 DODGE NEON ECU

junction block. A label on the underside of the PDC
cover identifies the locations of the ABS fuses.
(2) Inspect the 25-way electrical connector at the
CAB for damaged, spread, or backed-out wiring ter-
minals. Verify that the 25-way connector is fully
inserted in the socket of the CAB. Be sure that wires
are not stretched tight or pulled out of the connector.
(3) Verify that all the wheel speed sensor connec-
tions are secure.
(4) Look for poor mating of connector halves or ter-
minals not fully seated in the connector body.
(5)
Check for improperly formed or damaged termi-
nals. All connector terminals in a suspect circuit should
be carefully reformed to increase contact tension.
(6) Look for poor terminal-to-wire connections.
This requires removing the terminal from the connec-
tor body to inspect it.
(7) Verify pin presence in the connector assembly
(8) Check for proper ground connections. Check all
ground connections for signs of corrosion, loose fas-
teners, or other potential defects. Refer to the wiring
diagrams for ground locations.
(9) Look for problems with the main power sources
of the vehicle. Inspect the battery, generator, ignition
circuits and other related relays and fuses.
If a visual check does not find the cause of the
problem, operate the car in an attempt to duplicate
the condition and record any trouble codes.
Most failures of the ABS disable the ABS function
for the entire ignition cycle even if the fault clears
before key-off. There are some failure conditions,
however, that allow ABS operation to resume during
the ignition cycle in which the trouble occurred even
if the trouble conditions are no longer present.
The following trouble conditions may result in
intermittent illumination of the amber ABS warning
lamp.
²Low system voltage. If Low System Voltage is
detected by the CAB, the CAB will turn on the ABS
Warning Lamp until normal system voltage is
achieved. Once normal voltage is seen at the CAB,
normal operation resumes.
²High system voltage. If high system voltage is
detected by the CAB, the CAB will turn on the
Amber ABS Warning Lamp until normal system volt-
age is achieved. Once normal voltage is again
detected by the CAB, normal ABS operation resumes.
Additional possible causes that may result in the
illumination of the amber ABS warning lamp are as
follows:
²Any condition that interrupts electrical current
to the CAB may cause the amber ABS warning lamp
to turn on intermittently.
²If PCI communication between the body control-
ler and the CAB is interrupted, the body controller
can turn on the amber ABS warning lamp.
TONE WHEEL
Tone wheels can cause erratic wheel speed sensor
signals. Inspect tone wheels for the following possible
causes:
²missing, chipped, or broken teeth
²contact with the wheel speed sensor
²wheel speed sensor to tone wheel alignment
²wheel speed sensor to tone wheel clearance
²excessive tone wheel runout
²tone wheel loose on its mounting surface
If a front tone wheel is found to need replacement,
the drive shaft must be replaced. No attempt should
be made to replace just the tone wheel. Refer to the
DIFFERENTIAL AND DRIVELINE group in this
service manual for removal and installation.
If a rear tone wheel is found to need replacement,
the rear hub and bearing must be replaced. No
attempt should be made to replace just the tone
wheel. Refer to the SUSPENSION group in this ser-
vice manual for removal and installation.
If wheel speed sensor to tone wheel contact is evi-
dent, determine the cause and correct it before
replacing the wheel speed sensor or tone wheel.
Check the gap between the speed sensor head and
the tone wheel to ensure it is within specifications.
Refer to SPECIFICATIONS in this section of the ser-
vice manual for the minimum and maximum wheel
speed sensor to tone wheel clearance.
Excessive wheel speed sensor runout can cause
erratic wheel speed sensor signals. Refer to SPECI-
FICATIONS in this section of the service manual for
the maximum allowed tone wheel runout. If tone
wheel runout is excessive, determine if it is caused
by a defect in the driveshaft assembly or hub and
bearing. Replace as necessary.
Tone wheels are pressed onto their mounting sur-
faces and should not rotate independently from the
mounting surface. Replacement of the front drive-
shaft or rear hub and bearing is necessary.
BRAKE FLUID CONTAMINATION
Indications of fluid contamination are swollen or
deteriorated rubber parts. Swelling indicates the
presence of petroleum in the brake fluid.
To test for contamination, put a small amount of
drained brake fluid in clear glass jar. If the fluid sep-
arates into layers, there is mineral oil or other fluid
contamination of the brake fluid.
If the brake fluid is contaminated, drain and thor-
oughly flush the brake system. Replace all the rubber
parts or components containing rubber coming into
contact with the brake fluid including: the master
cylinder; proportioning valves; caliper seals; wheel
cylinder seals; ABS hydraulic control unit; and all
hydraulic fluid hoses.
5 - 76 BRAKESPL
DIAGNOSIS AND TESTING (Continued)

NOTE: It is not necessary to bleed the entire
hydraulic system after replacing just the master cyl-
inder unless the brake system has been open to air
for an excessive amount of time or air is present in
the lines. Only the master cylinder must be bled
and filled.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
Review this entire section prior to performing any
mechanical work on a vehicle equipped with ABS.
This section contains information on precautions per-
taining to potential component damage, vehicle dam-
age and personal injury which could result when
servicing an ABS equipped vehicle.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.CAUTION: Brake fluid will damage painted sur-
faces. If brake fluid is spilled on any painted sur-
faces, wash off with water immediately.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: If welding work is to be performed on
the vehicle, using an electric arc welder, the CAB
connector should be disconnected during the weld-
ing operation.
CAUTION: The CAB 25-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
Many components of the ABS System are not ser-
viceable and must be replaced as an assembly. Do not
disassemble any component which is not designed to
be serviced.
MASTER CYLINDER
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
CAUTION: The vacuum in the power brake booster
must be pumped down before removing the master
cylinder to prevent the booster from sucking in any
contamination. This can be done by pumping the
brake pedal while the engine is not running until a
firm brake pedal is achieved.
(1) With the engine not running, pump the brake
pedal 4-5 strokes until the pedal feel is firm.
(2) Disconnect the negative (ground) cable from
the battery and isolate the cable.
(3) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(4) Disconnect the wiring harness connector from
the brake fluid level switch on the master cylinder
reservoir (Fig. 12).
Fig. 11 Bleeding Master Cylinder
1 ± WOODEN DOWEL
2 ± MASTER CYLINDER
5 - 78 BRAKESPL
SERVICE PROCEDURES (Continued)

(5) Disconnect the primary and secondary brake
tubes from master cylinder (Fig. 12). Install plugs in
the master cylinder outlet ports.
(6) Clean the area around where the master cylin-
der attaches to the power brake booster using a suit-
able brake cleaner such as MopartBrake Parts
Cleaner or an equivalent.
(7) Remove the 2 nuts attaching master cylinder to
power brake booster (Fig. 12).
(8) Slide the master cylinder straight out of the
power brake booster.
INSTALLATION
NOTE: The master cylinder must be bled before
installing it on the vehicle.
(1) Bleed the master cylinder before installing it
on the vehicle. Refer to MASTER CYLINDER
BLEEDING in SERVICE PROCEDURES within this
section of this service manual group.
(2) Wipe the face of the power brake booster clean
where the master cylinder seal comes in contact
when it's installed. Do not get any cleaner or debris
inside the booster.(3) Position the master cylinder on the studs of
power brake vacuum booster aligning the booster
push rod with the master cylinder push rod. Care-
fully push the master cylinder onto the studs until it
contacts the face of the booster.
(4) Install the two master cylinder mounting nuts
(Fig. 12). Tighten the mounting nuts to a torque of
28 N´m (250 in. lbs.).
(5) Connect the primary and secondary brake
tubes to the master cylinder primary and secondary
ports (Fig. 12). Tighten the nuts to a torque of 17
N´m (145 in. lbs.).
(6) Install the wiring harness connector on the
master cylinder reservoir fluid level switch.
(7) Install the battery and clamp in place.
(8) Connect the positive, then the negative
(ground) cable on the battery.
(9) Fill the master cylinder to the proper fill level.
(10) Road test the vehicle to ensure proper opera-
tion of the base and antilock brake systems.
INTEGRATED CONTROL UNIT
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Using a brake pedal holder, depress the brake
pedal past its first one inch of travel and hold it in
this position (Fig. 13). This will isolate the master
cylinder from the brake hydraulic system and will
not allow the brake fluid to drain out of the master
cylinder reservoir.
(2) Disconnect negative (ground) cable from the
battery and isolate the cable.
(3) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(4) Remove the one nut and one bolt securing the
air cleaner box in place, then disconnect the wiring
harness connector at the air inlet sensor.
(5) Lift the air cleaner box upward enough to clear
its grommeted alignment post (Fig. 14), then move
the air cleaner box forward just enough to access the
battery tray mounting bolts.
(6) Remove the 2 bolts, then the 2 nuts mounting
the battery tray to its bracket (Fig. 14). Remove the
battery tray.
Fig. 12 Master Cylinder
1 ± POWER BRAKE BOOSTER
2 ± CONNECTOR
3 ± BRAKE FLUID LEVEL SWITCH
4 ± MOUNTING NUTS
5 ± SECONDARY BRAKE TUBE
6 ± PRIMARY BRAKE TUBE
PLBRAKES 5 - 79
REMOVAL AND INSTALLATION (Continued)

(14) Refer to DISASSEMBLY AND ASSEMBLY in
this section of this group for the procedure on sepa-
rating and reattaching the CAB to the HCU.
INSTALLATION
(1) Install the ICU onto its mounting bracket.
(2) Install the 3 bolts attaching the ICU to the
mounting bracket (Fig. 17). Tighten the 3 mounting
bolts to a torque of 11 N´m (97 in. lbs.)
(3) Install the four brake tubes going to the brakes
into their respective outlet ports on the ICU HCU
(Fig. 15). Using a crow foot on a torque wrench,
tighten the four brake tube nuts to a torque of 17
N´m (145 in. lbs.).
NOTE: When installing the brake tubes from the
master cylinder on the HCU, the brake tube with the
small tube nut is to be installed in the forward-most
port on the HCU with the small end going toward
the master cylinder secondary port.
(4) Install the primary and secondary brake tubes
from the master cylinder onto the HCU (Fig. 15). Do
not completely tighten the primary and secondary
tubes at this time.
(5) Connect the primary and secondary brake
tubes to the master cylinder ports (Fig. 15).
(6) Using a crow foot on a torque wrench, tighten
the primary and secondary brake tube nuts at both
the master cylinder and HCU to a torque of 17 N´m
(145 in. lbs.).
CAUTION: Before installing the 25-way connector
in the CAB, be sure the seal is properly installed in
the connector.(7) Install the 25-way connector into the socket of
the CAB as follows:
²Position the 25-way connector in the socket of
the CAB and carefully push it down as far as possi-
ble (Fig. 16).
²When the connector is fully seated into the CAB
socket, push the connector lock inward. This pulls
the connector into the socket of the CAB and locks it
in the installed position.
(8) Position the battery tray back in place. Install
the two bolts, then the two nuts mounting the bat-
tery tray to its bracket (Fig. 14). Tighten the two
bolts and nuts to a torque of 15 N´m (135 in. lbs.).
(9) Reinstall the air cleaner box onto its grom-
meted alignment post (Fig. 14).
(10) Install the one nut and one bolt securing the
air cleaner box in place, then connect the wiring har-
ness connector at the air inlet sensor.
(11) Install the battery and clamp it in place.
Tighten the hold-down clamp bolt to a torque of 12
N´m (105 in. lbs.).
(12) Connect the positive, then the negative
(ground) cable on the battery.
(13) Bleed the base and the ABS hydraulic sys-
tems. Refer to ANTILOCK BRAKE SYSTEM
BLEEDING in this section of this service manual
group.
(14) Fill the master cylinder to the proper fill
level.
(15) Road test the vehicle to ensure proper opera-
tion of the base and antilock brake systems.
WHEEL SPEED SENSOR (FRONT)
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group for the
proper lifting procedure.
(2) Disconnect the wheel speed sensor cable con-
nector from the wiring harness on the inside of the
frame rail above the front suspension crossmember
(Fig. 18). The connector has a locking tab which that
must be pulled back before the connector release
tang can be depressed, releasing the connection.
(3) Remove the speed sensor cable grommet from
the retaining bracket attached to the brake hose on
the outside of the frame rail.
(4) Remove the bolt mounting the wheel speed sen-
sor head to the steering knuckle (Fig. 19).
Fig. 17 ICU Mounting Bolts
1 ± ICU
2 ± ICU MOUNTING BOLTS
PLBRAKES 5 - 81
REMOVAL AND INSTALLATION (Continued)

CAUTION: When removing a wheel speed sensor
from the knuckle, do not use pliers on the sensor
head. This may damage the sensor head. If the sen-
sor has seized, use a hammer and a punch to tap
the edge of the sensor head ear, rocking the sensor
side-to-side until free.
(5) Carefully, remove the sensor head from the
steering knuckle.(6) Remove the screw securing the wheel speed
sensor to the rear of the strut (Fig. 20). Remove the
wheel speed sensor.
INSTALLATION
CAUTION: Failure to install speed sensor cables
properly may result in contact with moving parts or
an over extension of cables causing an open cir-
cuit. Be sure that cables are installed, routed, and
clipped properly.
(1) Attach the wheel speed sensor to the strut
using the its mounting screw (Fig. 20).
(2) Install the wheel speed sensor head in the
steering knuckle (Fig. 19). Install the mounting bolt.
Tighten the mounting bolt to a torque of 12 N´m (105
in. lbs.).
(3) From the sensor bracket on the strut, loop the
sensor cable upward, then downward at the outside
of the frame rail. Install the speed sensor cable grom-
met onto the retaining bracket attached to the brake
hose on the outside of the frame rail.
(4) Loop the wheel speed sensor cable around the
bottom of the frame rail and connect it to the wiring
harness connector on the inside of the frame rail
(Fig. 18). Remember to push in the locking tab on the
connector.
(5) Install the tire and wheel assembly.
(6) Lower the vehicle.
(7) Road test vehicle to ensure proper operation of
the base brakes and ABS.
Fig. 18 Wiring Harness Connector
1 ± RIGHT FRONT WHEEL SPEED SENSOR CONNECTOR
2 ± RIGHT FRONT DRIVESHAFT
3 ± ENGINE OIL FILTER
Fig. 19 Wheel Speed Sensor
1 ± RIGHT FRONT WHEEL SPEED SENSOR
2 ± TONE WHEEL
Fig. 20 Wheel Speed Sensor At Strut
1 ± ABS WHEEL SPEED SENSOR ROUTING BRACKET (IF
EQUIPPED)
2 ± GROUND STRAP
3 ± GROUND STRAP SCREW
4 ± ABS SENSOR BRACKET SCREW (IF EQUIPPED)
5 - 82 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

(d) Remove mounting bolt and nut (Fig. 10) and
partially remove air cleaner assembly.
(e) Disconnect accelerator and speed control (if
equipped) cables after the assy. is removed from
position. Remove air cleaner assembly from vehi-
cle.
(4) Remove battery tray from bracket.
(5) Disconnect ground cable at battery tray
bracket.
(6) Disconnect back-up lamp switch connector.
(7) Remove bellhousing cap (Fig. 11).
(8) Disconnect clutch cable from release lever and
remove from transaxle (Fig. 11).
(9) Remove shift cable-to-bracket clips (Fig. 12).
(10) Disconnect shift selector and crossover cable
from levers (Fig. 12). Remove cables and secure out
of the way.
(11) Disconnect the vehicle speed sensor connector
(Fig. 13).
(12) Raise vehicle on hoist.
(13) Remove transaxle oil drain plug and drain oil
into a suitable container.
(14) Remove both axle shafts. Refer to Group 3,
Differential and Driveline for the correct procedures.
(15) Remove structural collar (Fig. 14).
(16) Remove the left engine-to-transaxle lateral
bending brace (Fig. 14).
(17) Remove bellhousing dust cover (Fig. 14).
(18) Remove the right engine-to-transaxle lateral
bending brace (Fig. 15).(19) Remove starter motor (Fig. 16).
(20) Remove drive plate-to-clutch module bolts.
(21) Support engine at oil pan with screw jack and
wood block.
(22) Remove transaxle upper mount thru-bolt.
Gain access to this bolt through the driver's side
wheel house (Fig. 17).
(23) Carefully lower engine and transaxle on screw
jack until proper removal clearance is obtained.
Fig. 10 Air Cleaner Assembly Removal/Installation
1 ± AIR CLEANER ASSY.
2 ± THROTTLE BODY DUCTFWD
Fig. 11 Clutch Cable at Transaxle
1 ± CLUTCH CABLE
2 ± TRANSAXLE
3 ± BELLHOUSING CAP
Fig. 12 Shift Cables at Transaxle
1 ± SHIFT CABLES
2 ± CLIPS
3 ± BRACKET
PLCLUTCH 6 - 9
REMOVAL AND INSTALLATION (Continued)

(8) Connect starter electrical harness and tighten
positive cable nut to 10 N´m (90 in. lbs.) torque.
(9) Install bellhousing dust cover (Fig. 14).
(10) Install left engine-to-transaxle bending brace
(Fig. 14).(11) Install structural collar (Fig. 14) as follows:
(a) Position collar and install all bolts finger
tight.
(b) Tighten the collar-to-oil pan bolts to 3 N´m
(30 in. lbs.) torque.
(c) Tighten the collar-to-transaxle bolts to 108
N´m (80 ft. lbs.) torque.
(d) Final torque the collar-to-oil pan bolts to 54
N´m (40 ft. lbs.) torque.
(12) Install the right lateral bending brace and
tighten bolts to 81 N´m (60 ft. lbs.) torque (Fig. 15).
(13) Install both front axle driveshafts. Refer to
Group 3, Differential and Driveline for the correct
procedures.
(14) Fill transaxle with suitable amount of Mopart
Manual Transaxle Lubricant (PN 04874465).
(15) Lower vehicle.
(16) Connect vehicle speed sensor connector (Fig.
13).
(17) Connect shift crossover and selector cables to
shift lever. Install cables to bracket and install
retaining clips (Fig. 12).
(18) Connect clutch cable to fork and secure to
transaxle (Fig. 11).
(19) Install bellhousing cap (Fig. 11).
(20) Connect back-up lamp switch connector.
(21) Connect ground strap to transaxle upper
mount bracket.
(22) Install battery lower tray and battery, and
tighten battery hold down clamp to secure battery.
(23) Install the air cleaner/throttle body assy. as
follows:
(a) Connect the accelerator and speed control (if
equipped) cables to the air cleaner/throttle body
assy.
(b) Install assy into position, making sure the
air cleaner locating slot is engaged to the battery
bracket tab, and tighten fasteners to 14 N´m (120
in. lbs.) torque.
(c) Verify throttle body duct is fully seated to
intake manifold and tighten clamp to 5 N´m (40 in.
lbs.) torque.
(d) Connect the Throttle Position Sensor (TPS)
and Idle Air Control (IAC) connectors.
(e) Connect proportional purge solenoid (PPS)
and crankcase vent hose from throttle body.
(24) Connect the battery cables.
(25) Road test vehicle and inspect for leaks.
Fig. 16 Starter Motor Removal/InstallationÐTypical
1 ± BOLT
2 ± GROUND
3±STARTER
4 ± BOLT
Fig. 17 Transaxle Upper Mount Thru-BoltÐTypical
1 ± MOUNT BRACKET
2 ± BOLT
3 ± MOUNT
PLCLUTCH 6 - 11
REMOVAL AND INSTALLATION (Continued)

AUTOMATIC TRANSMISSION OIL COOLER
Oil coolers are internal oil to coolant type, mounted
in the radiator lower tank (Fig. 9). Rubber oil lines
feed the oil cooler and the automatic transmission.
Use only approved transmission oil cooler hose. Since
these are molded to fit space available, molded hoses
are recommended. Tighten Oil Cooler Hose Clamps
to 2 N´m (18 in. lbs.).
ACCESSORY DRIVE BELTS
The accessory drive consist of two Poly-V type
drive belts (Fig. 10). One belt drives the generator,
the other drives the power steering pump and air
conditioning compressor (if equipped). The power
steering/air conditioning belt is tensioned by an auto-
matically controlled belt tensioner. The generator
belt is manually tensioned using an adjusting bolt
and a locking nut.
ENGINE BLOCK HEATER
The heater is mounted in a core hole (in place of a
core hole plug) in the engine block, with the heating
element immersed in coolant (Fig. 11). The engine
block heater is available as an optional accessory.
The heater is operated by ordinary house current
(110 Volt A. C.) through a power cord and connector
behind the radiator grille.
When in operation, the engine block heater can
provide easier engine starting and faster warm-up,
when vehicle is operated in areas having extremely
low temperatures.CAUTION: The power cord must be secured in its
retainer clips, and not positioned so it could con-
tact linkages or exhaust manifolds and become
damaged.
Fig. 9 Automatic Transmission Oil Cooler
1 ± CLAMPS
2 ± HOSES
Fig. 10 Accessory Drive Belts
1 ± GENERATOR BELT
2 ± AUTOMATIC BELT TENSIONER
3 ± POWER STEERING PUMP/A/C COMPRESSOR BELT
Fig. 11 Engine Block Heater
1 ± CORE PLUG
2 ± BLOCK HEATER
3 ± POWER CORD
7 - 6 COOLING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)