brake sensor ISUZU TROOPER 1995 Owner's Manual

5A3-4 REAR WHEEL ANTILOCK BRAKE SYSTEM
SPEED SENSOR
The speed sensor is single pole, variable reluctance
pick up, mounted
in the rear differential carrier. An
exciter ring
is press fit on the differential ring gear and
provides the signal for the sensor. The
signal generated is proportional
to the average
speed
of the rear wheels and is used by the electronic
brake control module
(EBCM) to determine locking
tendencies
of the rear wheels.
Fig. 5A3-4
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-5
REAR WHEEL ANTILOCK (RWAL} CONTROL PARTS LOCATION
Fig. 5A3-5
ELECTRONIC BRAKE CONTROL MODULE
The module is located at the front of the center console.
ANTILOCK VALVE (Dual solenoid electrohydraulic)
The valve is located on the front right side of engine room.
SPEED SENSOR/EXCITER RING
The sensor and exciter ring are located on the rear axle carrier.
REAR WHEEL ANTILOCK (RWAL) WARNING LIGHT
The light is located on the instrument panel.
Rear axle
Electronic
brake control module

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
•

5A3-16 REAR WHEEL ANTILOCK BRAKE SYSTEM
CHART E
Rear Wheels Lock with Hard Stops
(Rr. ABS and Brake Lights Self Check Properly)
• APPLY THE BRAKE PEDAL AND CHECK FOR STOP LIGHTS.
STOP LIGHTS WILL NOT ILLUMINATE.
CHECK STOP LIGHT SWITCH OR CIRCUIT, AND REPAIR AS
NECESSARY, AND RECHECK IT.
EXCITER RING IS MISSING, OR TEETH ARE MISSING.
REPLACE
THE EXCITER RING.
VOLTAGE
UNDER 650 mV ON AC SCALE
REPLACE
THE SPEED SENSOR, AND RECHEK SENSOR
OUTPUT.
REAR BRAKES OK.
REPLACE THE EBCM.
STOP LIGHTS OK.
• REMOVE THE SENSOR FROM THE REAR AXLE CASE, AND CHECK FOR MISSING EXCITER RING, OR TEETH MISSING.
EXCITER
RING IS PRESENT, AND TEETH ARE INTACT.
• REINSTALL
THE SENSOR AND RAISE REAR WHEELS TO
SAFELY CLEAR THE FLOOR.
• START ENGINE, AND TURN REAR WHEEL AT 5 MPH.
• REMOVE THE LEFT HAND KICK PANEL, AND USING A
VOLTMETER SET ON THE AC SCALE, CHECK FOR VOLTAGE AT THE TWO PINS OF THE SENSOR TEST
CONNECTOR.
VOLTAGE
OVER 650 mV ON AC SCALE
• REINSTALL
THE KICK PANEL, AND CHECK THE REAR BRAKE FOR MECHANICAL PROBLEMS SUCH AS GRABBING, LOCKING OR PULLING.
REAR BRAKES LOCK, GRAB OR PULL.
REPAIR THE REAR BRAKE PROBLEMS.
EBCM = Electronic Brake Control Module
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-17
DIAGNOSTIC TROUBLE CODES
FLASHOUT CODES CHART
CONDITION ACTION TO
TAKE
Rr. ABS light flashes 2 times. See Flashout Diagnostic
(High resistance
isolate circuit or malfunctioning EBCM) Trouble Code (DTC) 2
Rr. ABS light flashes 3 times. See Flashout DTC 3
(High resistance
dump circuit or malfunctioning EBCM)
Rr. ABS light flashes 4 times.
See Flashout DTC 4
(Closed rear wheel antilock valve switch)
Rr. ABS light flashes 5 times.
See Flashout DTC 5
System dumps
too many times in 2WD (2WD and 4WD vehicles)
condition
Occurs while making normal or hard stops. Rear brake may lock.
Rr. ABS light flashes 6 times.
See Flashout DTC 6
(Erratic speed sensor reading
while driving)
Rr. ABS light flashes 7 times. See Flashout DTC 7
Isolation output missing or antilock valve wiring shorted to ground
Rr. ABS light flashes 8 times.
See Flashout DTC 8
Dump
output missing or antilock valve wiring shorted to ground
Rr. ABS light flashes 9 times. See Flashout DTC 9
(High sensor resistance)
Rr. ABS light flashes 10 times.
See Flashout DTC 1 0
(Low sensor resistance)
Rr. ABS light flashes 11 times.
See Flashout DTC 11
Stop light switch circuit defective, condition indicated only when driving
above
56 km/h (35 mph)
Rr. ABS light flashes 13 times.
See Flashout DTC 13
(Speed processor check EBCM)
Rr. ABS light flashes 14 times.
See Flashout DTC 14
(Program check
EBCM)
Rr. ABS light flashes 15 times.
See Flashout DTC 15
(Memory failure EBCM)
NOTE:
• Codes 1, 12 and over 15 are not utilized for the diagnostic mode.
EBCM = Electronic Brake Control Module

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 5A3-31
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
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-33
FLASH OUT DIAGNOSTIC TROUBLE CODE 10
(LOW 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 UNDER 1000 OHMS
REPLACE SENSOR, AND 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 (16) IN EBCM
HARNESS CONNECTOR AND CHASSIS GROUND WHILE
SHAKING THE HARNESS.
ERRATIC RESISTANCE READING.
REPLACE SENSOR,
RECHECK RESISTANCE READING, AND RECHECK THE SELF CHECK.
EBCM
= Electronic Brake Control Module
Continued on the next page