DaimlerChrysler LH New Yorker 1994, Электронное руководство по обслуживанию

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ABS BRAKE SYSTEM DIAGNOSIS
GENERAL INFORMATION
WARNING: SOME OPERATIONS IN THIS SECTION
REQUIRE THAT HYDRAULIC TUBES, HOSES AND
FITTINGS BE DISCONNECTED FOR INSPECTION OR
TESTING PURPOSES.
CAUTION: REVIEW THIS ENTIRE SECTION PRIOR
TO PERFORMING ANY MECHANICAL WORK ON A
VEHICLE EQUIPPED WITH THE TEVES MARK IV
ANTI-LOCK BRAKE SYSTEM. THIS SECTION CON-
TAINS THE INFORMATION ON PRECAUTIONS PER-
TAINING TO POTENTIAL COMPONENT DAMAGE,
VEHICLE DAMAGE AND PERSONAL INJURY WHICH
COULD
RESULT WHEN SERVICING AN ABS
EQUIPPED VEHICLE.
CAUTION: Certain components of the Anti-Lock
Brake System (ABS) are not intended to be serviced
individually. Attempting to remove or disconnect
certain system components, may result in personal
injury and/or improper system operation. Only those
components with approved removal and installation
procedures in this manual should be serviced.
This section contains information necessary to diag-
nosis mechanical conditions which can affect opera-
tion of the Teves Mark IV Anti-Lock Brake System.
Specifically, this section should be used to help diag-
nose mechanical conditions which result in any of the
following.
(1) Anti-Lock Warning Lamp turned on.
(2) Brakes Lock on Hard Application
Diagnosis of conditions which are obviously me-
chanical in nature. Such as brake noise, brake pulsa-
tion, lack of power assist, turning on of the Red Brake
Warning Lamp or vehicle vibration during normal
braking. Should be directed to Group 5 Brakes in this
service manual. This also pertains to problems involv-
ing the parking brake system.
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 with-
out performing extensive diagnostic work. Given ad-
equate understanding of the operating principles and
performance characteristics of the ABS system. See
Section 1 of this manual to familiarize yourself with
the operating principles of the ABS system.
DEFINITIONS
Several abbreviations are used in this manual.
They are presented here for reference.
•
HCU—Hydraulic Control Unit
•
CAB—Controller Anti-Lock Brake
•
ABS—Anti-Lock Brake System
•
PSI—Pounds per Square Inch (pressure)
•
WSS—Wheel 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 cir-
cuits, do not ground or apply voltage to any of
the circuits unless instructed to do so by the
appropriate diagnostic procedure. These circuits
should only be tested using a high impedance multi-
meter, special tools or the DRB II scan tool as de-
scribed in this section. Power should never be re-
moved or applied to any control module with the
ignition in the ON position. Before removing or con-
necting 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 Amber 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 Warn-
ing Lamp continues to stay on. If it does refer to the
1993 M.Y. Teves Mark IV Anti-Lock Brakes Diagnos-
tic 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 10 mph to
complete the ABS start up cycle. If at this time the
ANTI-LOCK BRAKE SYSTEM 5 - 89