ignition ISUZU TROOPER 1995 Owner's Manual

5A3-6 REAR WHEEL ANTILOCK BRAKE SYSTEM
SYSTEM DIAGRAM
4WD
switch
To 4WD
light -----11~-----lGY 3
Diagnostic Of------0 7 connector
For test
1-----11---+--y 17 Speed
sensor 1-----lt-----L
16
To
stoplight -----,
Stoplight switch
•IJI-----B 15
EBCM Pin View
i
&l ~ IU _, :;) Q
~ _, 0 a: .... z
8 IU ~ c( a: liD (.) z 0 a: 1-(.) IU _, IU
Pressure differential warning switch
(at Combination valve)
r-----+-<1 ~+II•
I•
6 LgB Parking brake _.-MI ____ ___,I'\.JI.Jr-, switch
5
BP -----'
2 w ------------~~._~
GR
4 BrR
9 BrY
20A Fuse F-9
RWAL 10
A •
1• h Fuse C-10
warnmg IQ t (Instrument
Antilock valve panel)
Isolation
valve
~ 4il .J o--1> ~
Reset ~1.5il
I
sw.
Dump valve
(Engine compartment)
13 YG - ACC IG1 Ignition
82 81 switch
50 A
Batt.
10 GW + ,,
15A BOA Fuse C-14 Main (Instrument fuse panel)
RWAL=Rear Wheel Antilock
CONNECTOR View
Fig. 5A3-6
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-7
REAR WHEEL ANTILOCK (RWAL) SYSTEM DIAGNOSTICS
DIAGNOSIS PROCEDURE
The RWAL system contains 13 diagnostic trouble
codes
for system troubleshooting. With the ignition
key turned
ON, momentarily grounding the RWAL
diagnostic lead
with the "Rr ABS" light on will cause the
light
to flash out a diagnostic trouble code if a failure
has been detected and is in memory.
Some RWAL
diagnostic trouble codes require a road test in order
to
be set into the EBCM memory.
RWAL diagnostic trouble codes are cleared from
the
EBCM memory every time the ignition key is
turned off. If a diagnostic trouble code is not present, a
test drive
must be performed to reproduce the failure
and reset the code into
memory:
TEST DRIVING
1. Conduct a visual check of the following items to
see if any abnormalities exist:
(a) Service brake mechanism/hydraulic system
(See BRAKE SERVICING SECTION).
(b) Fuses #2, #7, #14 and main fuse
(c) RWAL-related connector (check for loose pins
and rust)
(d) EBCM and valve ground (check for looseness
and rust)
NOTE:
Check
(c) and (d) should be done with ignition key
turned
OFF.
If any abnormality is found, perform repairs as
required.
2. Turn the ignition switch ON. As a self-check, the
"Rr ABS" light should come on for approximately
2 seconds, then go
off and remain off.
If the "Rr ABS" light remains on or comes back
on, check
for diagnostic trouble codes by
momentarily grounding the RWAL diagnostic
lead
with the "Rr ABS" light on. -
If the "Rr
ABS" light self-check operates
properly, continue
with the test drive below.
3. Test driving vehicle:
(a) Start the engine and begin driving the vehicle.
(b) Accelerate to 40 mph.
(c) At least once, brake to a full stop using enough
brake pedal force
to activate the RWAL
system.
(d) Accelerate to 60 mph and continue to run at
this speed
for 5 minutes.
4. If a diagnostic trouble code is obtained.
inspect in accordance
with the appropriate
"FLASHOUT DIAGNOSTIC TROUBLE CODES
CHART".
If
no diagnostic trouble code is found, and the
"Rr ABS" and "BRAKE" light comes on, or if
any abnormal operation occurs during the
test drive, inspect in accordance
with CHART
C, "Rr ABS AND BRAKE LIGHTS ON".
5. If the "Rr ABS" or "BRAKE" light does not come
during the test drive, ask the customer under
what conditions the light came on. Then try to
duplicate the complaint condition
as closely as
possible.
If no problem is found, check all underhood
connections that supply power
to the RWAL and
ignition fuses, inspect
all RWAL harness
connectors, and inspect the
EBCM and anti-lock
valve ground connections.
Do not assume that the
EBCM is bad because the
"Rr ABS" or "BRAKE" lights are on. In most cases,
it is telling you it has found a problem elsewhere.
Fig. 5A3-7

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-13
Continued from the previous page
• CHECK AND REPAIR ALL CIRCUITS FUSE IS PROTECTING FOR SHORTS TO GROUND. REPLACE FUSE, AND RECHECK THE SELF CHECK. •
DISCONNECT
THE EBCM HARNESS CONNECTOR FROM
EBCM, AND TURN THE IGNITION KEY TO THE ON POSITION, CHECK FOR VOLTAGE BETWEEN PIN (13) AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
CONSTANT READING OF VOLTAGE OVER 9V CONSTANT READING OF VOLTAGE UNDER9V
Continued on the next page
EBCM -
Electronic Brake Control Module

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-15
CHART D
Rr. ABS and Brake Lights Flashing
• TURN THE IGNITION KEY TO THE OFF POSITION, AND DISCONNECT THE EBCM HARNESS CONNECTOR FROM EBCM AND IGN. KEY ON CHECK FOR VOLTAGE AT PIN {13) OF EBCM HARNESS CONNECTOR AND CHASSIS GROUND WHILE
SHAKING THE BODY HARNESS AND REAR BODY HARNESS.
REPAIR THE HARNESS FOR OPEN CIRCUIT, AND RECHECK • DISCONNECT BATTERY, AND CHECK FOR RESISTANCE AT PIN {7) OF THE EBCM HARNESS CONNECTOR AND CHASSIS GROUND WHILE SHAKING THE BODY
HARNESS AND REAR BODY HARNESS.
THE SYSTEM.
•
CHECK FOR RESISTANCE AT PIN {15) OF EBCM HARNESS
CONNECTOR, AND CHASSIS GROUND WHILE SHAKING THE BODY HARNESS AND REAR BODY HARNESS.
REPAIR OPEN CIRCUIT
IN WIRE TO PIN {15) CONNECTOR, AND RECHECK THE SYSTEM.
EBCM = Electronic Brake Control Module

5A3-18 REAR WHEEL ANTILOCK BRAKE SYSTEM
DIAGNOSIS PROCEDURE
FLASHOUT DIAGNOSTIC TROUBLE CODE 2
(HIGH RESISTANCE ISOLATE CIRCUIT OR MALFUNCTIONING EBCM)
Antilock valve
Isolate.
Retest SW.
(EBCM)
Dump
• DISCONNECT THE BATIERY GROUND CABLE.
• DISCONNECT THE EBCM HARNESS CONNECTOR FROM EBCM, AND
CHECK FOR RESISTANCE BETWEEN EBCM HARNESS CONNECTOR PIN (1) AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
CONSTANT READING
OF RESISTANCE 3 TO 6 OHMS
CHECK EBCM VALVE AND GROUND CONNECTION
NO
PROBLEM IN EBCMIVALVE AND GROUND CONNECTION.
CONNECT
EBCM TO HARNESS CONNECTOR THEN TURN IGNITION ON.
NO CODE
2 INDICATED
REPLACE ANTILOCK VALVE AND RECHECK
THE SELF CHECK AND RETEST VEHICLE.
PROBLEM FOUND REPAIR CONNECTION(S) AND/OR GROUND
CODE 2 RETURNS
REPLACE EBCM AND
RECHECK THE SELF CHECK.
EBCM
= Electronic Brake Control Module
4!1
Continued on the next page
•

5A3-20 REAR WHEEL ANTILOCK BRAKE SYSTEM
FLASHOUT DIAGNOSTIC TROUBLE CODE 3
(HIGH RESISTANCE DUMP CIRCUIT OR MALFUNCTIONING EBCM)
Anti lock valve
Isolate.
Reset SW.
(EBCM)
Dump
• DISCONNECT THE BATTERY GROUND CABLE.
• DISCONNECT EBCM HARNESS CONNECTOR FROM EBCM,
AND CHECK FOR RESISTANCE BETWEEN EBCM HARNESS CONNECTOR PIN (9) AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
CONSTANT READING
OF RESISTANCE 1 TO 3 OHMS
CHECK EBCM
VALVE AND GROUND CONNECTION
NO
PROBLEM IN EBCMIVALVE AND
GROUND CONNECTION.
CONNECT EBCM TO HARNESS CONNECTOR
THEN TURN IGNITION ON.
NO CODE 31NDICATED
REPLACE ANTILOCK
VALVE AND RECHECK THE SELF CHECK AND RETEST VEHICLE.
PROBLEM FOUND REPAIR CONNECTION(S) AND/OR GROUND
CODE 3 RETURNS
REPLACE EBCM
AND RECHECK THE SELF
CHECK.
EBCM
~ Electronic Brake Control Module
4Q
1.5 !l
Continued on the next page
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-23
Continued from the previous page
CONSTANT READING OF RESISTANCE UNDER 10K OHMS
REPLACE ANTILOCK VALVE, AND RECHECK THE SELF
CHECK. CONSTANT
READING
OF RESISTANCE OVER 10K OHMS
• DISCONNECT
THE EBCM HARNESS CONNECTOR FROM
EBCM, AND CHECK FOR RESISTANCE BETWEEN EBCM HARNESS CONNECTOR PIN (4) AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
CONSTANT READING
OF CONSTANT READING OF ERRATIC RESISTANCE READING RESISTANCE UNDER 100K OHMS
REPAIR SHORT IN VALVE RESET
WIRE FROM VALVE TO EBCM HARNESS CONNECTOR, AND
RECHECK THE SELF CHECK. RESISTANCE
OVER 100K OHMS
CONNECT
EBCM TO HARNESS
CONNECTOR, THEN TURN IGNITION
ON. REPAIR THE HARNESS
NO CODE 41NDICATED,
OR WHEN PRESS THE BRAKE PEDAL AS HARD AS POSSIBLE, CODE 4 RETURNS. CODE 4 RETURNS WITHOUT BRAKE APPLICATION
REPLACE ANTI LOCK VALVE AND RECHECK THE SELF CHECK AND RETEST VEHICLE. REPLACE EBCM, AND RECHECK THE SELF CHECK.
EBCM
-Electronic Brake Control Module

5A3-24 REAR WHEEL ANTILOCK BRAKE SYSTEM
FLASHOUT DIAGNOSTIC TROUBLE CODE 5
(SYSTEM DUMPS TOO MANY TIMES IN 2WD CONDITION)
4WD
(EBCM)
4WDSW.
I•
I • CHECK IF FAILURE OCCURS IN 2WD MODE OR 4WD MODE. I
I I (2WD MODE) (4WD MODE)
• DISCONNECT THE EBCM HARNESS CONNECTOR FROM • DISCONNECT THE EBCM HARNESS CONNECTOR FROM
EBCM. EBCM.
J I • DRIVE THE VEHICLE IN 2WD MODE. • TURN
THE IGNITION KEY TO "ON".
l I • CHECK FOR CONDITION OF THE REAR BRAKE SYSTEM. • SHIFT TO 4WD MODE.
I
I I I REAR BRAKES TEND REAR BRAKES ARE
~
• CHECK FOR VOLTAGE BETWEEN HARNESS CONNEC-
TO LOCK UP EASILY. NORMAL. TOR PIN (3) AND CHASSIS GROUND WHILE SHAKING
I I
THE HARNESS.
~ 1S
REPAIR REAR BRAKE REPLACE
ANTI LOCK EBCM harness
connector
SYSTEM, AND RETEST VALVE, AND
RETEST ·'"·. ~)l VEHICLE. VEHICLE. [1l21314l~ 5161718) .......
J9J1oJ11J12r13 14J15J1sJ 11] = Pin (3)
~-~\
~ -~~~
"!!'
ERRATIC RESISTANCE READING. I I CONSTANT READING OF VOLTAGE I I CONSTANT
READING OF VOLTAGE
UNDER 1 V OVER 1 V
REPAIR THE HARNESS I I REPLACE ANTILOCK VALVE, AND I I REPEAT 4WD INDICATOR
SWITCH, RETEST VEHICLE. AND RETEST VEHICLE.
EBCM
~ Electronic Brake Control Module
I
•

5A3-26 REAR WHEEL ANTILOCK BRAKE SYSTEM
Continued from the previous page
REPLACE
THE EXCITER RING OF AXLE, AND RETEST
VEHICLE.
REPLACE SPEED SENSOR (THIS FAILURE MAY BE INTERMITTENT DUE TO MOISTURE CONTAMINATION, AND
CANNOT ALWAYS BE DETERMINED BY THE ABOVE RESISTANCE CHECK). Continued
from the previous page
•
REINSTALL SENSOR AND RAISE THE REAR WHEELS TO CLEAR THE FLOOR.
• START THE ENGINE, AND TURN THE WHEELS AT 5 MPH. • USING A VOLTMETER SET ON THE AC SCALE, CHECK FOR VOLTAGE AT THE TWO PINS OF THE SENSOR TEST CONNECTOR.
• RECONNECT BATIERY AND EBCM
CONNECTOR.
• RECONNECT SENSOR HARNESS TO SPEED SENSOR.
• THEN TURN IGNITION ON.
IF DEFECTS STILL EXISTS IN SYSTEM AFTER ALL PREVIOUS
STEPS, REPLACE EBCM.
EBCM
= Electronic Brake Control Module
•

5A3-28 REAR WHEEL ANTILOCK BRAKE SYSTEM
Continued from the previous page
I
I CONSTANT READING OF CONSTANT READING OF I ERRATIC RESISTANCE READING. I RESISTANCE OVER 20K OHMS
RESISTANCE UNDER 20K OHMS
I CONNECT BATTERY AND EBCM REPAIR ISOLATION WIRE FOR A L REPAIR THE HARNESS. I HARNESS CONNECTOR, THEN SHORT TO GROUND BETWEEN
TURN IGNITION ON.
ANTILOCK VALVE AND EBCM, AND RECHECK THE SELF CHECK.
NO
CODE 7 INDICATED I I CODE 7 RETURNS J
I
REPLACE ANTI LOCK VALVE AND RECHECK THE SELF CHECK I AND RETEST VEHICLE. I REPLACE EBCM AND RECHECK THE SELF CHECK. I
EBCM -Electronic Brake Control Module
•