DaimlerChrysler LH New Yorker 1994, Electronic Service Manual

Page: 182 / 1203

If any component exhibits a fault during system
initialization or dynamic check, the (CAB) will illumi-
nate the Anti-Lock warning lamp and Traction Con-
trol Function Lamp. At this time both systems are
disabled.
DIAGNOSTIC MODE
To enter diagnostic mode, vehicle must be below 10
MPH. If vehicle speed is not below 10 MPH a no
response message is displayed by the DRB II scan
tool. The following are characteristics of the diagnos-
tic mode.
The amber Anti-Lock warning lamp and brake
warning lamp flash. If a hard fault, such as an Inlet
or Outlet Valve fault or Main Relay Power Circuit
failure fault is present. The warning lamps illuminate
without blinking and no diagnostic operations are
available until the fault condition is cleared.
Anti-Lock and Traction control operation are dis-
abled.
The valves in the valve body cannot be actuated
when vehicle speed is above 5 MPH. If valve actua-
tion is attempted above 5 MPH a vehicle in motion
message is displayed by the DRBII scan tool.
CONTROLLER ANTI-LOCK BRAKE (CAB)
Fault codes are kept in a Non-Volatile memory until
either erased by the technician using the DRB II scan
tool or automatically after 50 ignition cycles (key
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 using the DRB II
scan tool. More than one fault can be stored at a time.
The number of key cycles since the most recent fault
was stored is also displayed. Most functions of the
(CAB) and ABS system can be accessed by the techni-
cian for testing and diagnostic 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.
As soon as the condition goes away, the Anti-Lock
Warning Light is turned off. Although a fault code
will be set in most cases.
TEVES MARK IV ELECTRONIC SYSTEMS
DIAGNOSTICS
The Teves Mark IV Anti-Lock Brake System Diag-
nostics, beyond the basic mechanical diagnostics, sys-
tems and components covered earlier in this section.
Are accomplished by the use of the DRB II scan tool.
See testing procedures outlined in the Teves Mark IV
Anti-Lock Brakes Diagnostics Manual for 1994 M.Y.
vehicles.
Please refer to the above mentioned manual for any
further electronic diagnostics and service procedures
that are required on the Teves Mark IV Anti-Lock
Brake System.
ON-CAR ABS BRAKE SYSTEM SERVICE
GENERAL SERVICE PRECAUTIONS
The following are general cautions which should be
observed when servicing the Anti-Lock brake system
and/or other vehicle systems. Failure to observe these
precautions may result in Anti-Lock Brake System
component damage.
If welding work is to be performed on the vehicle,
using an electric arc welder, the (CAB) connector
should be disconnected during the welding operation.
The (CAB) connector should never be connected or
disconnected with the ignition switch in the ON posi-
tion.
Many components of the Anti-Lock Brake System
are not serviceable and must be replaced as an as-
sembly. Do not disassemble any component which is
not designed to be serviced.
CHECKING BRAKE FLUID LEVEL
CAUTION: Only use brake fluid conforming to DOT 3
specifications, such as Mopar or Equivalent. Do not
use any fluid which contains a petroleum base. Do
not use a container which has been used for petro-
leum based fluids or a container which is wet with
water. Petroleum based fluids will cause swelling
and distortion of rubber parts in the hydraulic brake
system. Water will mix with brake fluid, lowering the
fluid boiling point. Keep all brake fluid containers
capped to prevent contamination. Remove the front
cap of the master cylinder reservoir and fill to the
bottom of the split ring.
For the specific procedure for the inspection of
brake fluid level and adding of brake to the reservoir.
Refer to the Service Adjustments Section in this
group of the service manual.
BLEEDING TEVES MARK IV ANTI-LOCK
BRAKE SYSTEM
The Anti-Lock Brake System must be bled anytime
air is permitted to enter the hydraulic system, due to
disconnection of brake lines, hoses of components.
If the (HCU) is removed from the vehicle, both the
Base Brake System and the Anti-Lock Brake System
must be bled using the appropriate procedure. It is
important to note that excessive air in the brake
system will cause a soft or spongy feeling brake pedal.
ANTI-LOCK BRAKE SYSTEM 5 - 91