1995 ISUZU TROOPER Workshop Manual

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-25
FLASHOUT DIAGNOSTIC TROUBLE CODE 6
(ERRATIC SPEED SENSOR READING WHILE DRIVING)
(EBCM)
Speed sensor
Test connectors Speed sensor
• DISCONNECT THE BATTERY GROUND CABLE.
• DISCONNECT THE EBCM HARNESS CONNECTOR FROM EBCM, AND
CHECK FOR RESISTANCE BETWEEN HARNESS CONNECTOR PINS, (17
AND 16) WHILE SHAKING THE HARNESS FROM SPEED SENSOR TO EBCM.
EBCM harness connector
Pin (17)
ERRATIC RESISTANCE READING.
REPAIR LOOSE CONNECTION
IN THE SPEED SENSOR
CIRCUITS; CHECK FOR DIRTY OR LOOSE PINS AND FRAYED OR SHORTED CONNECTORS AND RETEST VEHICLE.
METAL CHIPS ARE PRESENT.
DRAIN
AND CLEAN DIFFERENTIAL. CHECK EXCITER RING FOR BROKEN OR CHIPPED TEETH. RETEST VEHICLE.
TEETH ARE DAMAGED, OR LATERAL RUNOUT OF EXCITER
RING IS VISIBLE.
Continued on the next page
CONSTANT READING 1000 TO 2000 OHMS
•
CHECK FOR A BUILD-UP OF METAL CHIPS ON SPEED
SENSOR MAGNETIC POLE PIECE.
NO METAL CHIPS ARE PRESENT.
• ROTATE EXCITER RING,
AND CHECK FOR DAMAGE TO TEETH.
TEETH
ARE INTACT, AND NO VISIBLE LATERAL RUNOUT IS OBSERVED.
Continued on the next page
EBCM
= Electronic Brake Control Module

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
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-27
FLASHOUT DIAGNOSTIC TROUBLE CODE 7
(ISOLATION OUTPUT MISSING OR ANTI LOCK VALVE WIRING SHORTED TO
GROUND)
Anti lock valve
Isolate.
ResetSW. 40
(EBCM)
Dump
• DISCONNECT THE ANTILOCK VALVE CONNECTOR, AND CHECK FOR RESISTANCE BETWEEN THE VALVE ISOLATION SOLENOID PIN (4) AND
THE VALVE GROUND PIN (3) IN THE VALVE CONNECTOR.
Valve
connector
CONSTANT READING OF RESISTANCE UNDER 3 OHMS
REPLACE ANTILOCK VALVE, AND RECHECK THE SELF CHECK.
CONSTANT READING OF RESISTANCE 3 TO 6 OHMS
• DISCONNECT
THE BATTERY. • DISCONNECT THE EBCM HARNESS CONNECTOR FROM EBCM, AND CHECK FOR RESISTANCE BETWEEN THE ISOLATION PIN (1) OF EBCM HARNESS CONNECTOR AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
Continued on the next page
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
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-29
FLASHOUT DIAGNOSTIC TROUBLE CODE 8
(DUMP OUTPUT MISSING OR ANTILOCK VALVE WIRING SHORTED TO GROUND)
Isolate.
Reset SW.
(EBCM)
Dump
• DISCONNECT THE ANTILOCK VALVE CONNECTOR, AND CHECK FOR RESISTANCE BETWEEN THE VALVE DUMP SOLENOID PIN (1) AND THE VALVE GROUND PIN (3) IN THE VALVE CONNECTOR.
Valve
connector
CONSTANT READING OF RESISTANCE UNDER 1 OHM
REPLACE ANTILOCK VALVE, AND RECHECK THE SELF CHECK.
CONSTANT READING OF RESISTANCE 1 TO 3 OHMS
• DISCONNECT
THE BATIERY.
• DISCONNECT THE EBCM HARNESS CONNECTOR FROM EBCM, AND CHECK FOR RESISTANCE BETWEEN THE
DUMP PIN (9) OF EBCM HARNESS CONNECTOR AND CHASSIS GROUND WHILE SHAKING THE HARNESS.
Pin (9)
Continued on the
next page
EBCM
-Electronic Brake Control Module

5A3-30 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
l CONNECT BA TIERY AND
EBCM REPAIR DUMP WIRE FOR A SHORT I REPAIR THE HARNESS. J HARNESS CONNECTOR, THEN TO GROUND BETWEEN ANTILOCK TURN IGNITION ON.
VALVE AND EBCM, AND RECHECK THE SELF CHECK.
l NO CODE 81NDICATED I I CODE 8 RETURNS I
l REPLACE ANTI LOCK VALVE AND RECHECK THE SELF CHECK I I REPLACE EBCM AND RECHECK THE SELF CHECK. I AND RETEST VEHICLE.
EBCM = Electronic Brake Control Module
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-31
FLASHOUT DIAGNOSTIC TROUBLE CODE 9
(HIGH SENSOR RESISTANCE)
(EBCM)
Speed
sensor
Speed sensor
• DISCONNECT THE SENSOR HARNESS CONNECTOR FROM SPEED ..--..., SENSOR, AND CHECK FOR RESISTANCE BETWEEN THE TWO SENSOR
PINS WHILE SHAKING THE HARNESS.
CONSTANT READING
OF RESISTANCE OVER 2500 OHMS
REPLACE SENSOR, RECHECK RESISTANCE READING, AND RECHECK THE SELF CHECK.
CONSTANT READING OF RESISTANCE 1000 TO 2500 OHMS
• RECONNECT SENSOR HARNESS
CONNECTOR TO SPEED SENSOR.
• DISCONNECT
BATTERY AND DISCONNECT EBCM HARNESS
CONNECTOR FROM EBCM, AND CHECK FOR RESISTANCE BETWEEN PIN (17) AND PIN (16) IN EBCM HARNESS CONNECTOR
WHILE SHAKING THE HARNESS.
EBCM
harness connector
ERRATIC RESISTANCE READING.
REPLACE SENSOR, RECHECK RESISTANCE READING, AND RECHECK THE SELF CHECK.
EBCM
- Electronic Brake Control Module
Continued on the next page

5A3-32 REAR WHEEL ANTILOCK BRAKE SYSTEM
Continued from the previous page
I
I CONSTANT READING OF I CONSTANT
READING OF I ERRATIC RESISTANCE READING. I RESISTANCE 1000 TO 2500 OHMS
RESISTANCE OVER 2500 OHMS
I CHECK
EBCM AND/OR SPEED I SENSOR CONNECTION. REPAIR
OPEN SENSOR
WIRES FROM EBCM TO SPEED SENSOR, I REPAIR THE HARNESS. I
CHECK FOR DIRTY OR LOOSE PIN CONNECTIONS AT ALL CONNECTORS, AND RECHECK THE SELF CHECK.
1 • RECONNECT BATIERY AND EBCM HARNESS I PROBLEM FOUND; REPAIR CONNECTION(S). I CONNECTOR.
• RECONNECT SENSOR HARNESS TO SPEED SENSOR.
• THEN TURN IGNITION ON.
1 NO CODE 9 INDICATED I CODE 9 RETURNS I
J REPLACE
SPEED SENSOR (THIS
FAILURE MAY BE l RECHECK ALL PROCEDURE STEPS. I INTERMITIENT DUE TO MOISTURE CONTAMINATION, AND
J
CANNOT ALWAYS BE DETERMINED BY THE ABOVE
RESISTANCE CHECK).
IIF DEFECTS STILL EXISTS IN SYSTEM AFTER ALL PREVIOUS I STEPS, REPLACE EBCM.
EBCM
= Electronic Brake Control Module
•