sensor ISUZU TROOPER 1995 Repair Manual

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

ABS-2E
NO TROUBLE CODE
SELECT MODE
FO:DATA LIST
F1: NOT USED
F2:TROUBLE CODE
SELECT MODE
F3:SNAP SHOT
F4:CLEAR CODE
F5:ACTUATOR TEST
SELECT MODE
F6:WHEEL SENSORS
*note 1
ABS-2E
NO DATA!
CHECK ALDL CONN.
SEE CHART 1
4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-13
There is no trouble code in ABS system.
(In case of trouble, trouble code is displayed)
Select
desired mode (see following explanation of modes). (Scroll up and
down by key III. m operation.)
Chances are
that the picture as shown in the box appears next to the 8th
picture.
It is displayed when there is no communication between TECH 1
and the EBCM. The
following causes are considered:
CHART
1:
There are three different situations in which EBCM does not communicate
with TECH 1:
1) Disconnection of Data Link Connector (ALDL) Harness
Check
to see "ABS" warning light is normally actuated with IGN being
ON. lfthe light is not actuated, harness abnormality is suspected.
2) While driving (wheel speed values inputted)
No problem in running the vehicle after communicating with TECH 1
while the vehicle stops.

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-15
3. EXPLANATION OF MODES
Mode FO: OAT A LIST
FO: DATA LIST can display the
conditions
of sensors and switches as
well as the ONfOFF operation of
solenoid valves as commanded by the
EBCM.
In case of system abnormality,
the trouble area can be roughly
identified
with the data displayed.
Mode
F2: TROUBLE CODE
F2: TROUBLE CODE can display the
past (history) Diagnostic Trouble Codes
(DTCs) stored
by the EBCM. When
some
trouble occurs and a TROUBLE
CODE is set in this mode, the faulty
area can
promptly be located by
checking the associated Trouble Code
No.
Mode
F3: SNAPSHOT
F3: SNAPSHOT can help locate the
cause
of trouble by storing and
displaying the data
from a specific
period
of vehicle operation.
Mode
F4: CLEAR CODES
F4: CLEAR CODES erases the DTC
stored by the control unit.
Mode F5: ACTUATOR TEST
F5: ACTUATOR TEST can make sure if
the system-related motor, solenoid
valves, and hydraulic circuit function
normally. If there is still a problem in
the operation of the system even after
making electrical repairs, ACTUATOR
TEST may uncover another problem.
(note
1) This mode can be used under
the
following conditions:
No
trouble code is stored. (note 1)
The vehicle is not in motion. (note 2)
This mode should be selected before
starting the engine.
note
1: As this mode forcibly operates
actuators (solenoid valves,
relays, motor, etc.), the control
unit may be damaged if this
test
is conducted on damaged
actuators. Therefore, be sure
to repair all electrical faults
and make sure no
DTC is
stored before using this mode. note
2: If a vehicle speed (30 km/h
(18.6
mph)
or more) is detected
during the ACTUATOR
TEST,
the test function will auto­
matically stop.
Mode
F6: WHEEL SENSORS
F6: WHEEL SENSORS can check to
detect such speed sensor trouble as
EBCM's self-diagnosing function fails to
detect, including excessive gap in each
speed sensor,
momentary cut-off of
sensor signal, etc.

5A4-16 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
MODE FO: DATA LIST (When connected (communication with EBCM) while warning light is
off)
The data displayed by MODE FO: OAT A LIST are as follows:
Display Content OK/NG Criteria for Data
FL WHEEL SPEED km/h (mph) • Start the vehicle and make sure of linear change in each
FR WHEEL SPEED wheel speed.
• Turn each wheel by hand and make sure that each speed RL WHEEL SPEED data changes.
RR WHEEL SPEED
UVR MONITOR
Voltage • About 5V with key ON
VALVE RELAY INACTIVE • ACTIVE with key ON
ACTIVE
Voltage •
About 5V with brake pedal
BRAKE SWITCH • About OV with brake pedal
released
OPEN (Released)
• CLOSE
with brake pressed
CLOSE (Pressed) • OPEN with brake pedal released
ABSWARNING ACTIVE
• To be ACTIVE usually
LIGHT
INACTIVE
WHL. SENSOR RES. FAULT • Normal, if OKAY
OKAY
-FL SOL. VALVE ACTIVE • To be INACTIVE usually
FR SOL. VALVE INACTIVE
REAR SOL. VALVE
P. MOTOR RELAY ACTIVE • To be INACTIVE usually
INACTIVE
OFF-ROAD-INPUT Voltage A/T 1 L, R: less than O.SV
Other: 3 ±O.SV
MIT 1, 2, R: more than 4.0V
Other:
3 ± O.SV
T/F SWITCH OPEN • 4WD: CLOSE
CLOSE •
2WD: OPEN
As for ABS vehicle speed unit, km/h and mph are displayed alternately through Key F7.
•

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-17
MODE FO: DATA LIST (When connected (communication with EBCM) while warning light is
on)
._,. The data displayed by MODE FO: DATA LIST are as follows:
Display
Content OK/NG Criteria for Data
FL WHEEL SPEED
km/h (mph) • Start the vehicle and make sure of linear change in each
FR WHEEL SPEED wheel speed.
• Turn each wheel by hand and make sure that each speed RL WHEEL SPEED data changes.
RR WHEEL SPEED
UVR MONITOR Voltage • About OV with key ON
VALVE RELAY INACTIVE • INACTIVE with key ON
ACTIVE
Voltage • About 5V with brake pedal
BRAKE
SWITCH • About OV with brake
pedal released
OPEN (Released) • CLOSE with brake pressed
CLOSE (Pressed) • OPEN with brake pedal released
ABSWARNING ACTIVE • To be ACTIVE usually
LIGHT
INACTIVE
WHL.
SENSOR RES. FAULT • Normal, if OKAY
OKAY
FL SOL. VALVE ACTIVE • To be ACTIVE usually
FR SOL. VALVE INACTIVE
REAR SOL. VALVE
P. MOTOR RELAY
ACTIVE • To be INACTIVE usually
INACTIVE
OFF-ROAD-INPUT Voltage A/T 1 L, R: less than 0.5V
Other:
3 ±0.5V
MIT
1, 2, R: more than 4.0V
Other:
3 ± 0.5V
T/F SWITCH OPEN • 4WD: CLOSE
CLOSE •
2WD: OPEN
As for ABS vehicle speed unit, km/h and mph are displayed alternately through Key F7.

5A4-18 4-WHEEL ANTILOCK BRAKE SYSTEM (ABS)
MODE F2: TROUBLE CODE
The stored diagnostic trouble codes and their brief explanations are displayed in Mode: F2.
NOT PRESENT ...... Now normal, though faulty before.
PRESENT ............... Now faulty
NO TROUBLE CODES
ABS-2E
NO TROUBLE CODES
CHART 2 TROUBLE CODE
Code Code
12 Start code
14 EBCM function
15 Power voltage drop
21 G-sensor
22 Brake light switch
23 Transmission input
32 Motor&motor relay
41 FL wheel valve
42 FR wheel valve
44 Rear wheel valve
SELECT MODE FO:DATA LIST
F1: NOT USED F2:TROUBLE CODE
I
l (F2)
TC51:NOT PRESENT FRONT LEFT
WHEEL SENSOR OPEN (YESJ
(YES) J--_j
ABS-2E TC NOT PRESENT
51. 52, 62 SEE CHART 2 (YESJ
(YES)
l
SELECT MODE FO: DATA LIST
Fl:NOT USED F2:TROUBLE CODE
Chart No.
-
B-3
B-4
B-5
B-6
B-7
B-8
B-9
All the diagnostic trouble codes
and
their explanations stored by
EBCM are displayed.
On completion of displaying all the
diagnostic trouble codes and
their
explanations, all the diagnostic
trouble codes
only will be
displayed again.
Code Code
45 Valve relay
51 FL wheel speed sensor
52 FR wheel speed sensor
53 RL wheel speed sensor
54 RR wheel speed sensor
61 FL wheel speed sensor
62 FR wheel speed sensor
63 RL wheel speed sensor
64 RR wheel speed sensor
65 Sensor signal input
Chart No.
B-10
B-11
B-12
B-13
•

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-31
MODE F6: WHEEL SENSORS
When conducting the wheel sensor test, note the following:
1) Accelerate vehicle only slightly above 20 km/h (12 mph).
2) When this speed is attained, put transmission into neutral and allow vehicle to coast to a halt. (Parking
brake may be engaged slightly.)
3) When vehicle is at a standstill, actuate either foot brake or parking brake.
When the
wheel speed sensor test is being performed, the output or speed value of all four sensors is
monitored
by TECH 1. When the output of wheel sensors becomes too low to convert into speed value, the
last known vehicle speed is displayed and the values are fixed. If wheel sensors are normal, it is at the
vehicle speed
of 5 km/h (3 mph) or less that their output is lost. Therefore, if all the fixed speed values are
less than 5 km/h (3 mph), the wheel sensors are normal. If one or more of the four speed values is more
than 5 km/h
(3 mph), it suggests that the following abnormalities have occurred to the sensor(s):
1. Excess gap between the sensor and sensor rotor.
2. Broken or damaged sensor rotor teeth.
3. Momentary open in sensor harness.

5A4-32 4-WHEEL ANTI LOCK BRAKE SYSTEM (ABS)
TECH 1 Display Key Operation
INSTRUCT I ON: This explains MODE F6.
DRIVE VE-Drive vehicle at 20 km/h (12 mph).
HICLE AT 20km/h Press the YES key for the next display.
AND THEN (YES)
RELEASE GAS Release accelerator pedal while driving, and put transmission into neutral.
PEDAL, DISENGAGE Press the YES key for the next display.
TRANSMISSION
AND (YES)
AS SOON AS THE After coasting to a halt with transmission in neutral, apply brakes
VEHICLE HAS immediately.
STOPPED APPLY Press the YES key for the next display.
BRAKES (YES) This completes instructions as to F6.
The test will be started with the next display.
BEGIN TEST Let's begin the test.
DRIVE VE-Carry out the test according to the display.
HICLE AT 20km/h ** indicates the wheel speed value into which the output of each sensor ** ** ** ** has been converted.
Decelerate vehicle by coasting until it comes to a halt. (Parking brake may
DECREASE VEHICLE be slightly engaged.)
SPEED TO Okm/h
** ** ** **
MEASURED WHEEL Make sure that there is no significant difference among the wheel speed
SPEED THRESHOLDS values.
** **
** ** The
data indicate 3-5 km/h (2-3 mph).
SEE CHART 6 (YES) See CHART 6 .. Refer to CHART C-2 for check procedure.
To obtain mph in
MODE: F6, display mph in MODE: FO once and thereafter, change to MODE:F6.

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-33
PIN-OUT CHECKS
Connect Pinout Box J-35592 to 35-Pin Electronic Brake Control Module connector as described in this section.
~ Perform checks with high impedance digital multimeter J-39200 or equivalent.
Ignition
Multi meter Measure
No. Circuit to be Tested
Switch Scale/Range between Nominal Value Note Position
Pin Number
1 Ignition enable OFF 20DCV 1 (+), 10 (-) OV to 0.1V
ON 20DCV
1 (+), 10 (-) 11.5Vto 14.5V
2
Valve relay OFF n 32, 10 continuity: OK
no continuity: NG
OFF 200.Q 17,27 75 to 120n
3 Motor relay OFF n 14, 10 continuity: OK
no continuity: NG
OFF 200Q 17,28 70 to 90n
4
Diode ON n 29 (+), 32 (-) Replace(+) and
(-)with each
29 (-), 32 (+) other and check
to see a variation
of continuity/
no continuity.
5
Stop light switch OFF 20DCV 25, 10 11.5V to 14.5V Press brake pedal
6 Ground connection OFF 200Q 32, 10 Less than 2.Q Valve relay
32,20
32,34
7 FL solenoid valve OFF 200Q 2,32 0.6 to 1.8Q
8 FR solenoid valve OFF 200Q 35,32 0.6 to 1.8n
9 Rr solenoid valve OFF 200Q 18,32 0.6 to 1.8n
10 FL speed sensor OFF 2k.Q 22,4 0.8k to 1.3kn Internal Resistance
OFF 200k.Q 22, 10 more than 100kn Insulation Resistance
OFF 200mACV 22,4 more than 200mV Turn wheel at 1RPS
11 FR speed
sensor OFF 2k.Q 23,21 0.8k to 1.3k.Q Internal Resistance
OFF 200k.Q 23, 10 more than 100k.Q Insulation Resistance
OFF 200mACV 23,21 more than 200mV Turn wheel at 1RPS
12 RL speed sensor OFF 2k.Q 8,9 0.8k to 1.3k.Q Internal Resistance
OFF 200k.Q 8, 10 more than 100k.Q Insulation Resistance
OFF 200mACV 8,9 more than 200mV Turn wheel at 1RPS
13 RR speed sensor OFF 2k.Q 24,26 0.8k to 1.3k.Q Internal Resistance
OFF 200k.Q 24, 10 more than 100k.Q Insulation Resistance
OFF 200mACV 24,26 more than 200mV Turn wheel at 1RPS
14 G-sensor OFF 200.Q 13, 1 less than 100n
15 Transmission-Input ON n 16,20 continuity A/T
(L, R shift lever
position)
no
continuity
(other shift
position)
20DCV 16 (+), 20 (-) 11.5V to 14.5V
(M/T-1, 2, R)
ov
(other shift
position)
16 Transfer-Input ON 20DCV 15 (+), 20 (-) 11.5-14.5V (2H)
OV (4H, 4L)

!! 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 .....