stop start CHEVROLET PLYMOUTH ACCLAIM 1993 Service Manual

LUBRICATION AND MAINTENANCE
CONTENTS
page page
CHASSIS AND BODY .................... 19
DRIVETRAIN ........................... 16 ENGINE
................................ 8
GENERAL INFORMATION .................. 1
GENERAL INFORMATION INDEX
page page
Classification of Lubricants .................. 1
Fluid Capacities .......................... 4
Fuel Usage .............................. 1
Hoisting Recommendations .................. 5
Introduction .............................. 1 Jump Starting Procedure
.................... 4
Parts and Lubricant Recommendations ......... 1
Parts Requiring No Lubrication ............... 4
Severe Service ........................... 1
Towing Recommendations ................... 7
INTRODUCTION
Chrysler Corporation has compiled recommended
lubrication and maintenance schedules and proce-
dures to help reduce premature wear or failure over
a broad range of operating conditions. When select-
ing the proper maintenance schedule, the climate
and operating conditions must be considered. A vehi-
cle subjected to severe usage requires service more
frequently than a vehicle used for general transpor-
tation.
PARTS AND LUBRICANT RECOMMENDATIONS
When service is required, Chrysler Corporation rec-
ommends that only Mopar tbrand parts, lubricants
and chemicals be used. Mopar tprovides the best en-
gineered products for servicing Chrysler Corporation
vehicles.
SEVERE SERVICE
If a vehicle is operated under any of the following
conditions, it is considered severe service.
² Extremely dusty areas.
² 50% or more of vehicle operation in 32ÉC (90ÉF) or
higher temperatures.
² Prolonged idling ( such as, vehicle operation in
stop and go traffic).
² Frequent short running periods. Not allowing en-
gine to warm to operating temperatures.
² Police or taxi usage.
FUEL USAGE
All Chrysler Corporation engines require the use of
unleaded fuel to reduce exhaust emissions. Use fuel
with a minimum octane rating of 87,(R + M)/2. See
Engine section of this group for Fuel Recommenda-
tions.
CLASSIFICATION OF LUBRICANTS
Only lubricants that are endorsed by the following
organizations standards should be used to service a
Chrysler Corporation vehicle.
² Society of Automotive Engineers (SAE)
² American Petroleum Institute (API)
² National Lubricating Grease Institute (NLGI)
ENGINE OIL
SAE GRADE RATING INDICATES ENGINE OIL VISCOSITY
² SAE 30 = single grade engine oil.
² SAE 5W-30 = multiple grade engine oil.
API QUALITY CLASSIFICATION.
² SG service engine oil is a high quality crankcase
lubricant designed for use in all naturally aspirated
engines.
² SG/CD service engine oil is a high quality crank-
case lubricant designed for use in most naturally as-
pirated and turbocharged gasoline or diesel engines.
GEAR LUBRICANTS
SAE ratings also apply to multiple grade gear lu-
bricants. In addition, API classification defines the
lubricants usage.
Ä LUBRICATION AND MAINTENANCE 0 - 1

(3) On disabled vehicle, place gear selector in park
or neutral and set park brake. Turn off all accesso-
ries. (4) Connect jumper cables to booster battery. RED
clamp to positive terminal (+). BLACK clamp to
negative terminal (-). DO NOT allow clamps at oppo-
site end of cables to touch, electrical arc will result
(Fig. 1). Review all warnings in this procedure. (5) On disabled vehicle, connect RED jumper cable
clamp to positive (+) terminal. Connect BLACK
jumper cable clamp to engine ground as close to the
ground cable attaching point as possible (Fig. 1).
CAUTION: Do not crank starter motor on disabled
vehicle for more than 15 seconds, starter will over-
heat and could fail.
(6) Allow battery in disabled vehicle to charge to
at least 12.4 volts (75% charge) before attempting to
start engine. If engine does not start within 15 sec-
onds, stop cranking engine and allow starter to cool
(15 min.), before cranking again.
DISCONNECT CABLE CLAMPS AS FOLLOWS:
² Disconnect BLACK cable clamp from engine
ground on disabled vehicle.
² When using a Booster vehicle, disconnect BLACK
cable clamp from battery negative terminal. Discon-
nect RED cable clamp from battery positive terminal.
² Disconnect RED cable clamp from battery positive
terminal on disabled vehicle.
HOISTING RECOMMENDATIONS
Refer to Owner's Manual provided with vehicle for
proper emergency jacking procedures.
WARNING: THE HOISTING AND JACK LIFTING
POINTS PROVIDED ARE FOR A COMPLETE VEHI-
CLE. WHEN THE ENGINE OR REAR SUSPENSION IS REMOVED FROM A VEHICLE, THE CENTER OF
GRAVITY IS ALTERED MAKING SOME HOISTING
CONDITIONS UNSTABLE. PROPERLY SUPPORT OR
SECURE VEHICLE TO HOISTING DEVICE WHEN
THESE CONDITIONS EXIST.
TO HOIST OR JACK VEHICLE SEE FIG. 2 THROUGH 7:
Fig. 1 Jumper Cable Clamp Connections
Fig. 2 Hoisting and Jacking PointsÐAY Body
Fig. 3 Hoisting and Jacking PointsÐAC Body
Ä LUBRICATION AND MAINTENANCE 0 - 5

² SG service engine oil is a high quality crankcase
lubricant designed for use in all naturally aspirated
engines. If SG service engine oil is used in turbo-
charged engine, change engine oil at every 4 800
km (3,000 miles) or three months.
² SG/CD service engine oil is a high quality crank-
case lubricant designed for use in most naturally as-
pirated and turbocharged gasoline or diesel engines.
FLEXIBLE FUEL VEHICLES
Vehicles operated using Flexible Fuel (M85) re-
quire engine oil that meet or exceed Chrysler Stan-
dard MS-9214. Mopar Flexible Fuel engine oil or
equivalent should be used when adding or changing
crankcase lubricant. The API symbol (Fig. 1) on the
container indicates the viscosity grade, quality and
fuel economy ratings of the lubricant it contains. Use
ENERGY CONSERVING II motor oil with API SER-
VICE SG or SG/CD classification.
ENGINE OIL ADDITIVES
Chrysler Corporation recommends that Mopar En-
gine Oil Supplement or equivalent be used when fric-
tion and corrosion reducing materials added to the
crankcase lubricant is desired.
CRANKCASE OIL LEVEL INSPECTION
CAUTION: Do not overfill crankcase with engine oil,
oil foaming and oil pressure loss can result.
Inspect engine oil level approximately every 800
kilometers (500 miles). Position vehicle on level sur- face. With engine OFF, allow enough time for oil to
settle to bottom of crankcase, remove engine oil level
indicator (dipstick) and wipe clean. Install dipstick
and verify it is seated in the tube. Remove dipstick,
with handle above tip, take oil level reading (Fig. 2).
Add oil only if level is below MIN or ADD mark on
dipstick.
ENGINE OIL CHANGE
Change engine oil at mileage and time intervals
described in Lubrication and Maintenance Schedules.
Position the vehicle on a level surface. Hoist and
support vehicle on safety stands. Refer to Hoisting
and Jacking Recommendations in this group. Place a
suitable 3.8 liter (4 qt.) drain pan under crankcase
drain. Remove drain plug from crankcase. Inspect
drain plug threads for stretching or other damage.
Replace drain plug and gasket if damaged. Install
drain plug in crankcase. Lower vehicle and fill
crankcase with specified type and amount of engine
oil described in this section. Start engine and inspect
for leaks. Stop engine and inspect oil level.
ENGINE OIL FILTER
SELECTING OIL FILTER
Chrysler Corporation recommends a Mopar or
equivalent oil filter be used when replacement is re-
quired. A replacement filter must be designed to
withstand 1756 kPa (256 psi) of internal pressure.
OIL FILTER REPLACEMENT
Position a drain pan under the oil filter. Using a
suitable oil filter wrench (Fig. 3) loosen filter. When
filter separates from adapter nipple, tip gasket end
upward to minimize oil spill. Remove filter from ve-
hicle. With a wiping cloth, clean the gasket sealing
surface (Fig. 4) of oil and grime. Wipe off oil residue
from below oil filter adapter.
TO INSTALL NEW OIL FILTER: Lightly lubricate oil filter gasket with engine oil or
chassis grease. Thread filter onto adapter nipple.
When gasket makes contact with sealing surface,
tighten filter one full turn. If necessary use a filter
wrench, do not over tighten. Add oil, verify crank-
case oil level and start engine. Inspect for oil leaks.
RECOMMENDED VISCOSITY GRADES
Fig. 1 API Symbol
Fig. 2 Oil Level Indicator DipstickÐTypical
Ä LUBRICATION AND MAINTENANCE 0 - 9

HYDRAULIC SYSTEM CONTROL VALVES INDEX
page page
ABS Brake Proportioning Valve Operation ...... 27
General Information ....................... 26
Hydraulic System Service Procedures ......... 27 Non-ABS Proportioning Unit Operation
........ 26
Pressure Differential Warning Light Switch ...... 26
Testing ABS Proportioning Valves ............ 29
GENERAL INFORMATION
Most models not equipped with an Anti-Lock brak-
ing system have a combination hydraulic system con-
trol valve in the brake hydraulic system (Fig. 1). The
valve is attached to the frame rail below the master
cylinder.
The control valve assembly combines a warning
switch with a dual proportioning valve (Fig. 2) Proportioning valves balance front to rear braking
by controlling at a given ratio, the increase in rear
system hydraulic pressure above a preset level. Un-
der light pedal application, the valve allows full hy-
draulic pressure to the rear brakes. There is only one valve assembly in each vehicle,
see Valve Application Chart. During any service pro-
cedures identify valve assemblies by part number as
well as split point (PSI) and slope.
PRESSURE DIFFERENTIAL WARNING LIGHT
SWITCH
The hydraulic brake system, on non-ABS vehicles,
is split diagonally. The left front and right rear
brakes are part of one system. And the right front and left rear are part of another. Both systems are
routed through, but hydraulically separated by a Pres-
sure Differential Switch. The function of the Pressure
Differential Switch is to alert the driver of a malfunc-
tion in the brake system. If hydraulic pressure is lost in one system, the
warning light switch will activate a red light on the
instrument panel, when the brake pedal is depressed.
At this point the brakes require service. However, since
the brake systems are split diagonally the vehicle will
retain 50% of its stopping capability in the event of a
failure in either half. The warning light switch is the latching type. It
will automatically center itself after the repair is
made and the brake pedal is depressed. The instrument panel bulb can be checked each time
the ignition switch is turned to the start position or the
parking brake is set.
NON-ABS PROPORTIONING UNIT OPERATION
The proportioning valve section operates by trans-
mitting full input pressure to the rear brakes up to a
certain point. This is called the split point. Beyond this
point it reduces the amount of pressure increase to the
rear brakes according to a certain ratio. On light pedal applications equal brake pressure will
be transmitted to the front and rear brakes. On heavier
pedal applications the pressure transmitted
Fig. 1 Brake Combination Valve And Warning Switch Location
Fig. 2 Switch and Valve Assembly
5 - 26 BRAKES Ä

The primary functions of the (CAB) are:
² (1) Detect wheel locking tendencies.
² (2) Control fluid modulation to the brakes while in
Anti-Lock mode.
² (3) Monitor the system for proper operation.
² (4) Provide communication to the DRB II while in
diagnostic mode. The (CAB) continuously monitors the speed of each
wheel, through the signals generated at the Wheel
Speed Sensors, to determine if any wheel is begin-
ning to lock. When a wheel locking tendency is de-
tected, the (CAB) will isolate the master cylinder
from the wheel brakes. This is done by activating the
Isolation Valves. The (CAB) then commands the ap-
propriate Build or Decay valves to modulate brake
fluid pressure in some or all of the hydraulic circuits.
The fluid used for modulation comes from the booster
servo circuit. The (CAB) continues to control pres-
sure in individual hydraulic circuits until a locking
tendency is no longer present. The (ABS) system is constantly monitored by the
(CAB) for proper operation. If the (CAB) detects a
fault, it can disable the Anti-Lock braking function.
Depending on the fault, the (CAB) will light one or
both of the brake warning lamps. The (CAB) contains a System Diagnostic Program
which triggers the brake system warning lamps
when a system fault is detected. Faults are stored in
a diagnostic program memory. There are 19 fault
codes that may be stored in the (CAB) and displayed
through the DRB II. These fault codes will remain in
the (CAB) memory even after the ignition has been
turned off. These fault codes will remain in memory
until they are cleared with the DRB II, or automati-
cally erased from the memory after (50) ignition
switch on/off cycles.
CONTROLLER ANTI-LOCK BRAKE (INPUTS)
² Four wheel speed sensors.
² Boost pressure transducer.
² Primary pressure transducer.
² Low fluid level switch.
² Differential pressure switch.
² Parking brake switch.
² Dual function pressure switch (warning pressure
only)
² Stop lamp switch.
² Ignition switch.
² System relay voltage.
² Ground.
² Low Accumulator
CONTROLLER ANTI-LOCK BRAKE (OUTPUTS)
²Ten modulator valves-3 decay, 3 build and 4 isola-
tion.
² Red Brake warning lamp.
² Amber Anti-Lock Warning Lamp.
² System relay actuation. ²
Diagnostic communication.
ABS SYSTEM DIAGNOSTIC CONNECTOR
The Bendix Anti-Lock system diagnostic connector
is located under the lower dash panel or in the area
of the fuse box (Fig. 8). The fuse box is located be-
hind the access panel that is on the bottom portion of
the dash panel, left of the steering column. The diag-
nostics connector is a blue 6 way connector.
ANTI-LOCK SYSTEM RELAYS AND WARNING
LAMPS
PUMP/MOTOR RELAY
Pump/Motor power is supplied by the Pump/Motor
Relay. The Pump/Motor relay is located inside the
Power Distribution Center (PDC). The relay coil is
energized by a ground from the Dual Function Pres-
sure Switch. See (Fig. 9) for the location of the pump/
motor relay in the (PDC).
SYSTEM RELAY
The (ABS) Modulator Valves and Anti-Lock Warn-
ing Lamp Relay are controlled through a System Re-
lay. The System relay is located on the top left inner
fender behind the headlight (Fig. 10). The system re-
lay provides power to the (CAB) for modulator valve
operation (pins 47 and 50) after the start-up cycle
when the ignition is turned on.
ANTI-LOCK WARNING LAMP RELAY
The Anti-Lock Warning Lamp is controlled by the
Yellow Light Relay. See (Fig. 10) for location behind
the left headlight. With the relay de-energized, the
lamp is lit. When the system relay is energized by
Fig. 8 A.B.S. Diagnostic Connector Location
5 - 82 ANTI-LOCK 10 BRAKE SYSTEM Ä

Brake Warning Lamp may indicate reduced
braking ability. The following procedure should
be used to test drive an ABS complaint:(1) Ignition on. Turn the ignition to the ON position
without starting the car and wait until the Red Brake
Warning Lamp and Amber Anti-Lock Warning Lamp
turn off. This will allow the pump to charge the
accumulator to operating pressure. If the warning
lamp(s) do not turn off, go to step 3. (2) Ignition off for 15 seconds.
(3) Start car. Wait for displays to return to normal
operating mode before proceeding. (4) With Shift lever in PARK, slowly depress brake
pedal and release. (5) Drive vehicle a short distance. During this test
drive, be sure that the vehicle achieves at least 20 mph.
Then brake to at least one complete stop and accelerate
slowly back up to at least 20 mph. (6) If a functional problem with the A.B.S. system is
determined while test driving a vehicle. Refer to the
Bendix Anti-Lock 10 Diagnostics Manual for required
test procedures and proper use of the DRB II tester.
CAUTION: The following are general precautions that
should be observed when servicing and diagnosing
the ABS system and/or other vehicle systems. Failure
to observe these precautions may result in ABS
system damage.
(1) If welding work is to be performed on the vehicle
using an arc welder, the (CAB) should be disconnected
before the welding operation begins. (2) The (CAB) and hydraulic assembly 10 way con-
nectors should never be connected or disconnected with
the ignition on. (3) Some components of the ABS system are not
serviced separately and must be serviced as complete
assemblies. Do not disassemble any component which
is designated as non-serviceable. (4) Always de-pressurize the Hydraulic Accu-
mulator when performing any work that re-
quires disconnecting any hydraulic tube, flex
hose or fitting. The ABS system uses brake fluid
at high pressure. Failure to de-pressurize the
accumulator may result in personal injury
and/or damage to painted surfaces. Brake fluid will damage painted surfaces. If brake
fluid is spilled on any painted surfaces, wash off with
water immediately.
DE-PRESSURIZING HYDRAULIC ACCUMULA- TOR
The ABS pump/motor assembly keeps the hydraulic
accumulator charged between approximately 11,032
and 13,790 kPa (1600 and 2000 psi) anytime key is in the ON position. The pump/motor assembly
cannot run if the ignition is off or either battery ca-
ble is disconnected. Unless otherwise specified, the hydraulic accumu-
lator should be de-pressurized before disassembling
any portion of the hydraulic system. The following
procedure should be used to de-pressurize the hy-
draulic accumulator: (1) With ignition off, or either battery cable discon-
nected, pump the brake pedal a minimum of 40 times
using approximately 50 pounds of pedal force. A no-
ticeable change in pedal feel will occur when the ac-
cumulator becomes discharged. (2) When a definite increase in pedal effort is felt,
pump the pedal a few additional times. This will in-
sure removal of all hydraulic pressure from the
brake system.
WHEEL SPEED SENSOR CABLES
Proper installation of wheel speed sensor cables is
critical to continued ABS system operation. Be sure
that cables are installed and routed properly. Failure
to install cables in their retainers, as shown in Sec-
tion 3 of this manual. May result in contact with
moving parts or over extension of cables, resulting in
an open circuit.
MECHANICAL DIAGNOSTICS AND SERVICE
PROCEDURES
SPECIAL SERVICE TOOLS
Some diagnostic procedures in this section require
the use of special service tools. Each of these tools is
described below.
DRB II DIAGNOSTIC TESTER
Some of the diagnostic procedures that are ex-
plained in this section require the use of the DRB II
DIAGNOSTICS TESTER to insure that proper diag-
nostics are performed. Refer to those sections for
proper testing procedures and the DRB II manual for
its proper operational information.
MST-6163 PRESSURE TESTER
Some diagnostic procedures in this manual require
the use of the MST-6163 pressure gauge and adaptor
(Fig. 2). Pressure Gauge, Special Tool MST-6163 is
required to measure accumulator pressure during
certain phases of ABS operation. The pressure gauge
and adaptor should be installed as follows: (1) De-pressurize the accumulator by pumping the
brake pedal a minimum of 40 times with the ignition
off. The procedure is fully explained under De-Pres-
surizing Hydraulic Accumulator which is described
earlier in this System Diagnosis Section.
Ä ANTI-LOCK 10 BRAKE SYSTEM 5 - 89

CONTROLLER ANTI-LOCK BRAKE (CAB)
The (CAB) (Fig. 5) is a small control computer
which receives wheel speed information, controls An-
ti-Lock operation and monitors system operation.
ANTI-LOCK BRAKES OPERATION AND
PERFORMANCE
This Anti-Lock Braking System represents the cur-
rent state-of-the-art in vehicle braking systems and
offers the driver increased safety and control during
braking. This is accomplished by a sophisticated sys-
tem of electrical and hydraulic components. As a re-
sult, there are a few performance characteristics that
may at first seem different but should be considered
normal. These characteristics are discussed below.
More technical details are discussed further in this
section.
PEDAL FEEL
Since the Bendix Anti-Lock 6 Braking System uses
the conventional Booster/Master Cylinder. The brake
pedal feel during normal braking is the same as con-
ventional Non ABS equipped cars. When Anti-Lock is activated during hard braking
due to a wheel lockup tendency. Brake pedal effort
will increase do to the master cylinder pressure be-
ing isolated from the brake system. Some brake
pedal movement and associated noises may be felt
and herd by the driver. This is normal of a Anti-Lock
Braking System due to pressurized fluid being trans-
ferred to and from the wheel brakes.
ANTI-LOCK BRAKE SYSTEM OPERATION
During Anti-Lock Braking, brake pressures are
modulated by cycling electric solenoid valves. The cy-
cling of these valves can be faintly heard as a series
of popping or ticking noises. In addition, the cycling
may be felt as a pulsation in the brake pedal, al-
though no pedal movement will be noticed. If Anti-
Lock Operation occurs during hard braking, some pulsation may be felt in the vehicle body due to fore
and aft movement of the suspension as brake pres-
sures are modulated.
Although ABS operation is available at virtually
all vehicle speeds. It will automatically turn off at
speeds below 3 to 5 mph. Wheel lockup may be per-
ceived at the very end of an anti lock stop and is con-
sidered normal.
TIRE NOISE & MARKS
Although the ABS system prevents complete wheel
lock-up, some wheel slip is desired in order to
achieve optimum braking performance. During brake
pressure modulation, as brake pressure is increased,
wheel slip is allowed to reach up to 30%. This means
that the wheel rolling velocity is 30% less than that
of a free rolling wheel at a given vehicle speed. This
slip may result in some tire chirping, depending on
the road surface. This sound should not be inter-
preted as total wheel lock-up. Complete wheel lock up normally leaves black tire
marks on dry pavement. The Anti-Lock Braking Sys-
tem will not leave dark black tire marks since the
wheel never reaches a locked condition. Tire marks
may however be noticeable as light patched marks.
VEHICLE PERFORMANCE
Anti-Lock Brakes provide the driver with some
steering control during hard braking, however there
are conditions where the system does not provide any
benefit. In particular, hydroplaning is still possible
when the tires ride on a film of water. This results in
the vehicles tires leaving the road surface rendering
the vehicle virtually uncontrollable. In addition, ex-
treme steering maneuvers at high speed or high
speed cornering beyond the limits of tire adhesion to
the road surface may cause vehicle skidding, inde-
pendent of vehicle braking. For this reason, the ABS
system is termed Anti-Lock instead of Anti-Skid.
SYSTEM SELF-DIAGNOSTICS
The Bendix Anti-Lock 6 Brake System has been
designed with the following self diagnostics capabil-
ity. The self diagnostic ABS startup cycle begins when
the ignition switch is in the on position. An electrical
check is completed on the ABS components such as
Wheel Speed Sensor Continuity and System and
other Relay continuity. During this check the Amber
Anti-Lock Light is on for approximately 1-2 seconds. Further Functional testing is accomplished once
the vehicle is set in motion. (1) The solenoid valves and the pump/motor are ac-
tivated briefly to verify function. (2) The voltage output from the wheel speed sen-
sors is verified to be within the correct operating
range.
Fig. 5 Controller Anti-Lock Brake (CAB)
Ä ANTI-LOCK 6 BRAKE SYSTEM 5 - 115

In order to effectively diagnose an Anti-Lock Brake
System (ABS) condition. It is important to read Anti-
Lock Brake System Description. And to follow the
diagnostic procedures outlined in this section. Many conditions that generate customer complaints
may be normal operating conditions, but are judged to
be a problem due to not being familiar with the ABS
system. These conditions can be recognized without
performing extensive diagnostic work. Given adequate
understanding of the operating principles and perfor-
mance characteristics of the ABS system. See Section 1
of this manual to familiarize yourself with the operat-
ing principles of the ABS system.
DEFINITIONS
Several abbreviations are used in this manual. They
are presented here for reference.
² CABÐController Anti-Lock Brake
² ABSÐAnti-Lock Brake System
² PSIÐPounds per Square Inch (pressure)
² WSSÐWheel Speed Sensor
ABS COMPUTER SYSTEM SERVICE PRECAUTIONS
The ABS system uses an electronic control module,
the (CAB). This module is designed to withstand nor-
mal current draws associated with vehicle operation.
However care must be taken to avoid overloading the
(CAB) circuits. In testing for open or short circuits,
do not ground or apply voltage to any of the
circuits unless instructed to do so by the appro-
priate diagnostic procedure. These circuits should
only be tested using a high impedance multi-meter,
special tools or the DRB II tester as described in this
section. Power should never be removed or applied to
any control module with the ignition in the ON posi-
tion. Before removing or connecting battery cables,
fuses, or connectors, always turn the ignition to the
OFF position.
ABS GENERAL SERVICE PRECAUTIONS
TEST DRIVING ABS COMPLAINT VEHICLES
Most ABS complaints will require a test drive as a
part of the diagnostic procedure. The purpose of the
test drive is to duplicate the condition. Remember conditions that result in the turn-
ing on of the Red Brake Warning Lamp may
indicate reduced braking ability. The following
procedure should be used to test drive an ABS
complaint vehicle. Before test driving a brake complaint vehicle, note
whether the Red or Amber Brake Warning Lamp is
turned on. If it is the Red Brake Warning Lamp, refer
to the standard brake, Control Valves Section in the
brake group of this manual. If the Amber Anti-Lock
Warning light was/is on, read record and erase the
fault. While the Amber ABS Warning Lamp is on the
ABS system is not functional. When the Am- ber Anti-Lock Warning Lamp is on only the Anti-Lock
function of the brake system if affected. The standard
brake system and the ability to stop the car is not be
affected if only the Amber Anti-Lock Warning Lamp is
on. (1) Turn the key to the off position and then back to
the on position. Note whether the Amber ABS Warning
Lamp continues to stay on. If it does refer to the 1993
M.Y. Bendix Anti-Lock 6 Diagnostic Manual for the
required test procedures. (2) If the Amber ABS Warning Lamp goes out, shift
into gear and drive the car to a speed of 5 mph to
complete the ABS start up cycle. If at this time the
Amber ABS Warning Lamp goes on refer to the Bendix
Anti-Lock 6 Diagnostic Manual. (3) If the Amber ABS Warning Lamp remains OUT,
drive the vehicle a short distance. During this test
drive be sure that the vehicle achieves at least 25 mph.
Brake to at least one complete stop and again acceler-
ate to 25 mph. (4) If a functional problem with the A.B.S. system is
determined while test driving a vehicle. Refer to the
Bendix Anti-Lock 6 Diagnostics Manual for required
test procedures and proper use of the DRB II tester.
ABS BRAKE SYSTEM ON VEHICLE SERVICE
The following are general precautions which
should be observed when servicing and diagnos-
ing the ABS system and/or other vehicle systems.
Failure to observe these precautions may result
in ABS system damage. (1) If welding work is to be performed on a vehicle
using an arc welder, the (CAB) should be disconnected
before the welding operation begins. (2) The (CAB) and modulator assembly 10 way con-
nector should never be connected or disconnected with
the ignition in the on position. (3) Some components of the ABS system are not
serviced separately and must be serviced as complete
assemblies. Do not disassemble any component which
is designated as non-serviceable.
CAUTION: Brake fluid will damage painted surfaces.
If brake fluid is spilled on any painted surfaces, wash
off with water immediately.
WHEEL SPEED SENSOR CABLES
Proper installation of the Wheel Speed Sensor Cables
is critical to continued system operation. Be sure that
cables are installed, routed and clipped properly. Fail-
ure to install speed sensor cables as shown in the on
car service section of this manual. May result in
contact with moving parts or over extension of cables,
resulting in component failure and an open circuit.
5 - 124 ANTI-LOCK 6 BRAKE SYSTEM Ä

MECHANICAL DIAGNOSTICS AND SERVICE
PROCEDURES
SPECIAL SERVICE TOOL
Some diagnostic procedures in this section require
the use of the DRB II diagnostics tester. The proper
application and procedures for the use of this tool are
described below.
DRB II DIAGNOSTIC TESTER Some of the diagnostic procedures that are ex-
plained in this section require the use of the DRB II
Diagnostics Tester to insure that proper diagnostics
are performed. Refer to those sections for proper test-
ing procedures and the DRB II operators manual for
its proper operational information.
INTERMITTENT FAULTS
As with virtually any electronic system, intermit-
tent faults in the ABS system may be difficult to ac-
curately diagnose. Most intermittent faults are caused by faulty elec-
trical connections or wiring. When an intermittent
fault is encountered, check suspect circuits for: (1) Poor mating of connector halves or terminals
not fully seated in the connector body. (2) Improperly formed or damaged terminals. All
connector terminals in a suspect circuit should be
carefully reformed to increase contact tension. (3) Poor terminal to wire connection. This requires
removing the terminal from the connector body to in-
spect. (4) Pin presence in the connector assembly
If a visual check does not find the cause of the
problem, operate the car in an attempt to duplicate
the condition and record the Fault code. Most failures of the ABS system will disable Anti-
Lock function for the entire ignition cycle even if the
fault clears before key-off. There are some failure
conditions, however, which will allow ABS operation
to resume during the ignition cycle in which a fail-
ure occurred. If the failure conditions are no longer
present. The following conditions may result in inter-
mittent illumination of the Amber Anti-Lock Warn-
ing Lamp. All other failures will cause the lamp to
remain on until the ignition switch is turned off. Cir-
cuits involving these inputs to the (CAB) should be
investigated if a complaint of intermittent warning
system operation is encountered. (1) Low system voltage. If Low System Voltage is
detected by the (CAB), the (CAB) will turn on the
Amber Anti-Lock Warning Lamp until normal sys-
tem voltage is achieved. Once normal voltage is seen
at the (CAB), normal operation resumes. (2) Anti-Lock relay. If the relay fails to make the
ground circuit connection or is an intermittent
ground. The (CAB) will turn on the Amber Anti-Lock
Warning Light. (3) Excess decay, an extended pressure decay pe-
riod, will turn on the Amber Anti-Lock Warning
Light until the vehicle comes to a complete stop. Additionally, any condition which results in inter-
ruption of electrical current to the (CAB) or modula-
tor assembly. May cause the Amber Anti-Lock
Warning Lamp to turn on intermittently.
ABS BRAKE SYSTEM DIAGNOSTIC FEATURES
ABS SYSTEM SELF DIAGNOSIS
The ABS system is equipped with a self diagnostic
capability which may be used to assist in isolation of
ABS faults. The features of the self diagnostics sys-
tem are described below.
START-UP CYCLE
The self diagnostic ABS start up cycle begins when
the ignition switch is turned to the on position. An
electrical check is completed on the ABS components.
Such as Wheel Speed Sensor Continuity and System
and other Relay continuity. During this check the
Amber Anti-Lock Light is turned on for approxi-
mately 1- 2 seconds. Further Functional testing is accomplished once
the vehicle is set in motion.
² The solenoid valves and the pump/motor are acti-
vated briefly to verify function.
² The voltage output from the wheel speed sensors is
verified to be within the correct operating range. If the vehicle is not set in motion within 3 minutes
from the time the ignition switch is set in the on po-
sition. The solenoid test is bypassed but the pump/
motor is activated briefly to verify that it is
operating correctly.
CONTROLLER ANTI-LOCK BRAKE (CAB)
Fault codes are kept in a Non-Volatile memory un-
til either erased by the technician using the DRB II
or erased automatically after 50 ignition cycles (key
ON-OFF cycles). The only fault that will not be
erased after 50 (KEY CYCLES) is the (CAB) fault. A
(CAB) fault can only be erased by the technician us-
ing the DRB II diagnostic tester. More than one fault
can be stored at a time. The number of key cycles
since the most recent fault was stored is also dis-
played. Most functions of the (CAB) and ABS system
can be accessed by the technician for testing and di-
agnostic purposes by using the DRB II.
LATCHING VERSUS NON-LATCHING ABS FAULTS
Some faults detected by the (CAB) are latching; the
fault is latched and (ABS) is disabled until the igni-
tion switch is reset. Thus ABS is disabled even if the
original fault has disappeared. Other faults are non-
latching; any warning lights that are turned on, are
only turned on as long as the fault condition exists.
Ä ANTI-LOCK 6 BRAKE SYSTEM 5 - 125

ANTILOCK BRAKES OPERATION AND
PERFORMANCE
The Bendix Antilock 4 Brake System represents
the current state-of-the-art in vehicle brake systems
and offers the driver increased safety and control
during braking. This is accomplished by a sophisti-
cated system of electrical and hydraulic components.
As a result, there are a few performance characteris-
tics that may at first seem different but should be
considered normal. These characteristics are dis-
cussed below. More technical details are discussed
further in this section.
PEDAL FEEL
Since the Bendix Antilock 4 Brake System uses the
vehicle's conventional brake system power booster
and master cylinder. The brake pedal feel during
normal braking is the same as on a conventional
Non ABS equipped vehicle. When the Antilock system becomes activated dur-
ing hard braking due to a wheel lockup tendency.
The brake pedal effort will increase do to the master
cylinder pressure being isolated from the brake sys-
tem. Some brake pedal movement and associated
noises may be felt and heard by the driver. This is
normal operation of the Bendix Antilock 4 Brake
System due to pressurized brake fluid being trans-
ferred to and from the wheel brakes.
ANTILOCK BRAKE SYSTEM OPERATION
During Antilock Brake system operation, brake
pressures are modulated by cycling electric solenoid
valves. The cycling of these valves can be heard as a
series of popping or ticking noises. In addition, the
cycling may be felt as a pulsation in the brake pedal.
If Antilock operation occurs during a hard applica-
tion of the brakes, some pulsation may be felt in the
vehicle body due to fore and aft movement of vehicle
suspension components. Although ABS operation is available at virtually
all vehicle speeds, it will automatically turn off at
speeds below 3 to 5 mph. Wheel lockup may be per-
ceived at the very end of an anti lock stop and is con-
sidered normal.
TIRE NOISE & MARKS
Although the ABS system prevents complete wheel
lock-up, some wheel slip is desired in order to
achieve optimum vehicle braking performance. During brake fluid pressure modulation, as the
brake fluid pressure is increased, wheel slip is al-
lowed to reach up to 30%. This means that wheel
rolling speed is 30% less than that of a free rolling
wheel at a given vehicle speed. This slip may result
in some tire chirping, depending on the road surface.
This sound should not be interpreted as total wheel
lock-up. Complete wheel lock up normally leaves black tire
marks on dry pavement. The Antilock Brake System
will not leave dark black tire marks since the wheel
never reaches a locked condition. Tire marks may
however be noticeable as light patched marks.
VEHICLE PERFORMANCE
Antilock Brakes provide the driver with some
steering control during hard braking, however there
are conditions where the system does not provide any
benefit. In particular, hydroplaning is still possible
when the tires ride on a film of water. This results in
the vehicles tires leaving the road surface rendering
the vehicle virtually uncontrollable. In addition, ex-
treme steering maneuvers at high speed or high
speed cornering beyond the limits of tire adhesion to
the road surface may cause vehicle skidding, inde-
pendent of vehicle braking. For this reason, the ABS
system is termed Antilock instead of Anti-Skid.
SYSTEM SELF-DIAGNOSTICS
The Bendix Antilock 4 Brake System has been de-
signed with the following self diagnostic capabilities. The self diagnostic ABS startup cycle begins when
the ignition switch is turned to the on position. At
this time an electrical check is completed on the ABS
components such as Wheel Speed Sensor Continuity
and System and other Relay continuity. During this
check the Amber Antilock Light is on for approxi-
mately 1-2 seconds. Further Antilock Brake System functional testing
is accomplished once the vehicle is set in motion,
known as drive-off. (1) The solenoid valves and the pump/motor are ac-
tivated briefly to verify function.
Fig. 5 Controller Antilock Brake CAB
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 15