battery ISUZU TROOPER 1995 Repair Manual

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-5
DIAGNOSIS
GENERAL INFORMATION
ABS troubles can be classified to two types, those
which can be detected by the ABS warning light
and those which can be detected as a vehicle
abnormality by the driver.
In either case, locate the fault in accordance with
the "BASIC DIAGNOSTIC FLOWCHART" and repair.
Please refer to Section 5A, 5A1, 5A2, 5C for the
diagnosis
of mechanical troubles such as brake
noise, brake
judder (brake pedal or vehicle vibration
felt when braking), uneven braking, and parking
brake
trouble.
ABS SYSTEM SERVICE PRECAUTIONS
Required Tools and Items
Box Wrench
• Brake Fluid
Special Tool
Some diagnosis procedures in this section require
the installation of a special tool.
PINOUT BOX
In order to prevent damage to the 35-pin Electronic
Brake
Control Module (EBCM) connector, J-35592
pinout box should be installed on the EBCM
connector prior to probing any circuit with the
digital
multimeter. This pinout box is to be used
combined with J-35616 connector test adapter kit.
W IMPORTANT
Do not probe the 35-pin EBCM connector
without installing J-35592 pinout box. Damage
to connector terminals may occur if the pinout
box is not installed, resulting in improper
system operation. The following procedure
should be used to install J-35592 pinout box.
1. Ignition must be "OFF" when installing or
removing the 35-pin EBCM connector.
Fig. 5A4-3
2. Disconnect the 35-pin EBCM harness connector
by depressing the connector locking plate and
rotating
the connector toward the front of
vehicle.
3. Inspect the 35-pin connector for damage.
Connect J-35592 to the 35-pin connector.
4. Proceed with test as outlined in the diagnostic
procedure.
J-39200 HIGH IMPEDANCE MUL TIMETER
When circuit measurements are requested, use a
circuit tester
with high impedance.
COMPUTER SYSTEM SERVICE
PRECAUTIONS
The Antilock Brake System interfaces directly with
the Electronic Brake Control Module (EBCM) which
is a
control computer that is similar in some
regards
to the Engine Control Module. These
modules are designed to withstand normal current
draws associated with vehicle operation. However,
care
must be taken to avoid overloading any of the
EBCM circuits. In testing for opens or shorts, 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
with a high impedance multimeter (J-39200) or
special tools as described in this section. Power
should never be removed or applied to any control
module with the ignition in the "ON" position.
Before removing
or connecting battery cables,
fuses
or connectors, always turn the ignition switch
to the "OFF" position.
GENERAL SERVICE PRECAUTIONS
The following are general precautions which should
be observed when servicing and diagnosing the
Antilock Brake System and/or
other vehicle
systems. Failure
to observe these precautions may
result in Antilock Brake System damage.
If welding work is to be performed on the
vehicle using an electric arc welder, the EBCM
and valve block connectors should be
disconnected before the
welding operation
begins.
The
EBCM and valve block connectors should
never be connected or disconnected with the
ignition "ON".
Hydraulic units of the Antilock Brake System
are not separately serviceable and must be
replaced
as assemblies. Do not disassemble
any
component which is designated as non­
serviceable in
this Section.

5A4-6 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
If only rear wheels are rotated using jacks or
drum tester, the system will diagnose a speed
sensor
malfunction and the "ABS" warning
light will illuminate. But actually no trouble
exists. After inspection stop the engine once
and re-start it,
then make sure that the "ABS"
warning light does not illuminate.
If the battery has been discharged
The engine may stall if the battery has been
completely discharged and the engine is started via
a
jumper cable. This is because the Antilock Brake
System (ABS) requires a
large quantity of
electricity. In this case, wait until the battery is
recharged,
or set the ABS to a non-operative state
by removing the fuse for the ABS (40A). After the
battery has been recharged, stop the engine and
install the ABS fuse. Start the engine again, and
confirm that the ABS warning light does not light.
NOTE ON INTERMITTENTS
As with virtually any electronic system, it is difficult
to identify an intermittent failure. In such a case
duplicating the system malfunction during a test
drive
or a good description of vehicle behavior from
the customer may be helpful in locating a "most
likely" failed component or circuit. The symptom
diagnosis chart may also be useful in isolating the
failure. Most intermittent problems are caused by
faulty electrical connections or wiring. When an
intermittent failure is encountered, check suspect
circuits for:
Suspected harness damage.
• Poor mating of connector halves or terminals
not fully seated in the connector body (backed
out).
Improperly formed or damaged terminals.
TEST DRIVING ABS COMPLAINT
VEHICLES
In case that there has been an abnormality in the
lighting pattern of "ABS" warning light, the fault
can be located in accordance with the "DIAGNOSIS
BY 'ABS' WARNING LIGHT ILLUMINATION
PATTERN". In case of such trouble as can be
detected
by the driver as a vehicle symptom,
however, it is necessary to give a test drive
following the test procedure mentioned below,
thereby reproducing the symptom for trouble
diagnosis on a symptom basis:
1. Start the engine and make sure that the "ABS"
W/L goes OFF. If the W/L remains ON, it
means that the Diagnostic Trouble Code (DTC)
is stored. Therefore, read the code and
locate
the fault.
2. Start the vehicle and accelerate to 30 km/h (19
mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to 40
km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and ... ~
stop the vehicle.
6. Be cautious of abnormality during the test. If
theW/Lis actuated while driving, read the DTC
and locate the fault.
7. If the abnormality is not reproduced by the
test, make best efforts
to reproduce the
situation reported
by the customer.
8. If the abnormality has been detected, repair in
accordance
with the "SYMPTOM DIAGNOSIS".
NOTE:
Be sure to give a test drive on a wide, even
road
with a small traffic.
If an abnormality is detected, be sure to
suspend the test and start
trouble diagnosis at
once.
II ABS" WARNING LIGHT
When ABS trouble occurs to actuate "ABS"
warning light, the trouble code corresponding to
the trouble is stored in the EBCM. Only ordinary
brake is available with ABS being unactuated. Even
when "ABS" warning light is actuated, if the starter
switch is set
ON after setting it OFF once, the EBCM
checks
up on the entire system and, if there is no
abnormality, judges ABS to work currently and the
warning light is lit normally even though the
trouble code is stored.
NOTE:
Illumination of the "ABS" warning light
indicates that antilock braking is no longer
available. Power assisted braking without
antilock control is still available.
NORMAL OPERATION
II ABS" WARNING LIGHT
When the ignition is first moved from "OFF" to
"RUN", the amber "ABS" warning light will turn
"ON". The "ABS" warning light will turn "ON"
during engine starting and will usually stay "ON"
for approximately three seconds after the ignition
switch is returned to the "ON" position. The
warning light should remain "OFF" at all other
times.
•

5A4-10 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
TECH 1 TOOL
TECH 1 is an effective tool for the diagnosis of
electrical fault of Antilock Brake System (ASS) and
system check.
Although you can completely
diagnose the system without a TECH 1, using the
tool is quicker. In the following procedures, the
!TECH 11 symbol shows where the TECH 1 is used.
The
t::nettll symbol means the tool is not used.
1. WHAT CAN BE DONE WITH TECH 1
ON TECH 1
TECH 1 is a hand-held tester (Fig. 5A4-4).
Connected
to the Data Link Connector (DLC)
installed in the vehicle, it communicates with
ABS control unit (EBCM), thereby conducting
various diagnoses and tests.
Fig. 5A4-4
For this
vehicle, use ISUZU '90-'94
TRANSMISSION/ASS cartridge.
TECH 1 can check the following items:
(1) Input values of EBCM sensors and
switches, and
working conditions of
solenoid valves.
(2) Diagnostic Trouble Code (DTC) No.
(3) Incoming/outgoing data records.
(4) The function of ABS through the
operation
of the motor and solenoid
valves.
(5) Clearing DTCs stored in EBCM.
How to connect TECH 1 with the vehicle (Fig.
5A4·5, 5A4-6)
(1) Insert the program cartridge (TK02500B-1)
securely
into the TECH 1 main unit (J-38770-1).
(2) Attach the adapter to the cable.
(3) Plug the ISUZU 3-pin adapter (T A-02279-8) into
the adapter.
(4) Insert one end of the power plug into the TECH
1 and the other end into the cigarette lighter of
the vehicle.
The power plug may as well be coupled
directly
to the battery using the battery cable
adapter (J-38770-4).
(5) Turn the ignition key OFF, and connect TECH 1
with DLC (Orange colored).
Fig. 5A4-5
Data link Connector (Orange)
Fig. 5A4-6

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-21
MODE F5: ACTUATOR TEST
This mode is used to exercise the ABS system actuators and make sure they operate normally. Prior to the
test, pay attention
to the cautions below. (When checking the solenoid valve system, be sure to jack up the
vehicle.)
w CAUTION:
• Before testing, be sure that the brakes work normally.
• Make sure that the battery is fully charged.
Conduct the test
by two persons (A TECH 1 operator and a vehicle checker).
• Be sure to start actuator test with the engine stopped.
• Before testing, make sure that electrical trouble, if any, has been completely repaired. Conducting
tests
of ABS actuator with electrical circuit problem remaining uncorrected could damage the
control unit.
Selection Procedure:
SELECT MODE FO:DATA LIST
*
F5:ACTUATOR TEST
IUiJ
SELECT ACTUATOR * P. MOTOR RELAY FL SOL. VALVE
FR SOL. VALVE REAR SOL. VALVE
ABS W/L
----> Refer to CD
----> Refer to ®
----> Refer to @ ----> Refer to @
----> Refer to ®
NOTE:
F5; Actuator test procedure, the systems Q) to @
mentioned on the left can be checked four times
continuously as each system is checked once.
When checking more than
four times continuously,
the fifth check
must be started with a break of 10
minutes or more after the fourth to protect ABS
pump motor.
Select the desired test
by operating !I] 1[!] keys and press I ENT I key.

!! co U1 )> "" I .... w
(
EBCM
RR
ABS SPEED SENSOR
(RHl
.
RELAY:
UPSHIFT-2
""·,'-....."
M-11_
. ·r·---
..
C-39
M-12"-~.·
··..
> .. , ,·
~'
...
,
~~~~~
~.-· RELAY
& FUSE
BOX
· ••.
(FL-1,
FL-2, FL-6,
F-9~
'•
BATTERY HYDRAULIC
--+1--.-.
UNIT
C-33
--~----
C-34.
H-41
H-42
TRANSMISSION
(


~·~ rl r
( STARTER
SW
RR
ABS SPEED SENSOR
(LH)
\~· \'
-.
.
B-46
' G SENSOR
\
FUSE
BOX (C-3, C-4, C-10, C-14)
BRAKE
SW
(W/CRUISE CONTROL)
STOPLIGHT SW
(W/0
CRUISE CONTROL)
BRAKE PEDAL FRT
ABS
SPEED SENSOR
(LH)
(
"V )> ~ r-0 s 5 2
.... :e ::I: m
m r-l> 2 ~ r-0 0 ~ CCI ~ ~ m ~ Cl) -t m s: ~ ~ c.n t I w .....

5A4-50 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
CHART B-1
WITH THE KEY IN THE ON POSITION (BEFORE STARTING THE ENGINE),
WARNING LIGHT
{W/L) IS NOT ACTUATED.
IS W/L FUSE C-10 DISCONNECTED? j
I
IS W/L BURNT OUT? I
I
• TURN IGNITION OFF
• REMOVE EBCM CONNECTOR AND CONNECT PINOUT BOX
• TURN THE KEY ON AND MEASURE VOLTAGE BETWEEN TERMINAL 29 AND 10
I
I
BATTERYVOLTAGE I
I
CHECK CONTINUITY BETWEEN PINOUT BOX I TERMINALS 10, 20 AND 34 AND BODY GROUND
l
I CONTINUITY I
I • CHECK HARNESS FOR SUSPECTED DISCONNECTION I • NO FAULT FOUND: REPLACE EBCM
I
I
DISCONNECTED I
I L REPLACE FUSE J
I L DISCONNECTED J
I I REPLACE W/L BULB I
I
I
LOWVOLTAGE I
I
I
REPAIR HARNESS AND CONNECTOR I
I
I
NO CONTINUITY I
I I REPAIR HARNESS AND CONNECTOR I
•

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-53
CHART B-4 ~I
POWER VOLTAGE DROP (DIAGNOSTIC TROUBLE CODE 15)
INSPECT BATTERY VOLTAGE I (BATTERY CAPACITY CHECKI
I
$ ~
• TURN THE KEY OFF AND CONNECT PINOUT BOX I CHARGE OR REPLACE BATTERY I • TURN THE KEY ON AND MEASURE VOLTAGE BETWEEN PINOUT BOX TERMINAL 1 AND 10
I
I
l
HIGHER THAN 10V I I LOWER THAN 10V I
I I
• CHECK HARNESS/CONNECTOR FOR SUSPECTED I REPAIR HARNESS OR CONNECTOR l DISCONNECTION . FAULT FOUND:
REPAIR, AND PERFORM SYSTEM
SELF-CHECK
• NO FAULT FOUND: REPLACE EBCM

5A4-58 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
CHART B-8 I):Eeti((l
HYDRAULIC UNIT (HU) PUMP MOTOR AND MOTOR RELAY CIRCUIT ~
(DIAGNOSTIC TROUBLE CODE 32)
• WITH THE KEY TURNED OFF, CONNECT PINOUT BOX
• MEASURE RESISTANCE BETWEEN TERMINALS 17 AND28
I 70n-9on I I OTHER THAN 70n-9on I
I
CHECK CONTINUITY BETWEEN TERMINAL 141 AND10 I MEASURE RESISTANCE BETWEEN HU CONNECTORS I C34-6 AND C34-11
I
I I I
CONTINUITY j NO CONTINUITY j 1 70(l-9ooJ I OTHER THAN 70n-9on I
I I I REMOVE HU CONNECTOR CHECK CONTINUITY I REPAIR HARNESS BB07 I I REPLACE HU I AND CHECK CONTINUITY BETWEEN HU OR BB08 BETWEEN PINOUT BOX
CONNECTOR C33-3 TERMINAL 14 AND 10 AND BODY GROUND
I
I
I CONTINUITY I NO CONTINUITY j
I I REPAIR HARNESS BB27, BB06 (OPEN) I • CHECK FOR MOTOR GROUND • FAULT FOUND: REPAIR GROUND
I • NO FAULT FOUND: REPLACE HU
NO CONTINUITY I CONTINUITY J
I MEASURE VOLTAGE REPAIR HARNESS
BETWEEN HU CONNECTOR BB06, BB27
(GND
C33-2 AND BODY GROUND SHORT)
BATTERYVOLTAGE I $
. MOTOR RELAY REPAIR FUSE/HARNESS BETWEEN I ABNORMAL BATTERY AND C33-2/CONNECTOR • REPLACE HU
•

5A4-60 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
CHART B-1 0 [):Ee@]
VALVE RELAY ABNORMALITY (DIAGNOSTIC TROUBLE CODE 45) ~
• WITH THE KEY TURNED OFF, CONNECT PINOUT BOX
• MEASURE RESISTANCE BETWEEN THE TERMINALS 17 AND 27
I 1s-12oo 1 I OTHER THAN 75-1200 J
I
CHECK CONTINUITY
BETWEEN TERMINAL 32 J AND10 I_ REMOVE HU CONNECTOR AND MEASURE I RESISTANCE BETWEEN C34-6 AND C34-10
I
I
I I
CONTINUITY I
NO CONTINUITY/ I75-120n/ I OTHERS I
I I
I
MEASURE
VOLTAGE CHECK CONTINUITY I REPAIR HARNESS/ J I REPLACE HU I
BETWEEN HU HARNESS BETWEEN C34-7 AND CONNECTOR
C33-1 TO BODY GROUND C34-12 ON THE VEHICLE SIDE I
I I CONTINUITY I l NO CONTINUITY I
I I
CHECK CONTINUITY VEHICLE-SIDE
,. HU IS FAULTY J HU CONNECTOR C34-12 AND BODY • REPLACE
HU GROUND
I
I I
CONTINUITY j I NO CONTINUITY I
I I • HARNESS BB12 l REPAIR HARNESS BY02 I OPEN
• REPAIR HARNESS
I BATTERY VOLTAGE j OTHER I
I
• HU VALVE RELAY I REPAIR HARNESS /FUSE BETWEEN I TROUBLE BATTERY AND HU • REPLACE HU
~1111 .. 1 2 3 4 5 617 8 9 101112 =
•

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-73
ON-VEHICLE SERVICE
W CAUTION:
~ Replace all components included in repair kits used to service this system. Lubricate rubber parts with
clean, fresh brake fluid to ease assembly. Do not use shop air with in-line lubricators on brake parts,
as
damage to rubber components may result. If any hydraulic component is removed or brake line
disconnected,
it may be necessary to bleed part or all of the brake system.
NOTE:
The use of rubber hoses or parts other than those furnished specifically for the Anti lock Brake System may
lead to functional problems requiring major overhaul.
HYDRAULIC UNIT
5 (Located at the back
of the front fender) Removal
steps
1. Harness connector 2. Battery mounting bar 3. Brake pipes 4. Ground cable bolt 5. Bracket fixing bolt and nut 6. Bracket 7. Hydraulic unit fixing nuts 8. Hydraulic unit
Installation steps To install, follow the removal
steps in the reverse order.
1••1 REMOVAL
Fig. 5A4-15
I••IINSTALLATION
1. Harness connector
2. Battery mounting bar
3. Brake pipes
• After disconnecting brake pipe, cap or tape
the
openings of the brake pipe to prevent the
entry of foreign matter.
4. Ground cable bolt
5. Bracket fixing bolt and nut
6. Bracket
7. Hydraulic unit fixing nuts
8. Hydraulic unit
To install, follow the removal steps in the reverse
order,
noting the following points:
Torque
N·m Ob·ftl
Hydraulic unit fixing nuts 22 (16)
Bracket fixing bolt 24 (17)
Ground cable 14 (10)
Brake pipe (joint bolts) 16 (12)
• After installing the hydraulic unit, bleed brakes
completely.
See Section 5A "Hydraulic Brakes".