ISUZU KB P190 2007 Workshop Repair Manual

ELECTRICAL-BODY AND CHASSIS 8A-343
TROUBLESHOOTING
SPEEDOMETER
1. Speedometer and odometer do not function

Checkpoint Trouble Cause Countermeasure


Replace the vehicle speed
sensor

Vehicle speed sensor
malfunction

NG

Repair an open circuit in the
circuit or a poor connection at
the connectors Continuity between the vehicle
speed sensor and the meter,
or the fuse C14 (10A) and the
ground

Open circuit or poor connector
contact


Replace the case baseboard
assy

Use a meter tester to check
the speedometer function

Speedometer malfunction

NG
NG
OK
OK
Check the vehicle speed
sensor output
(4 pulses/1 rotation)




2. Speedometer pointer fluctuates
(May be wide fluctuation)

Replace the vehicle speed
sensor, or repair an open
circuit in the circuit or a
connectors Vehicle speed sensor
malfunction, or open circuit or
poor connector contact

NG


Replace the case baseboard
assy

Use a meter tester to check
the speedometer function

Speedometer malfunction

NG
OK
Check the speed sensor
output by using the
oscilloscope




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8A-344 ELECTRICAL-BODY AND CHASSIS
3. Speedometer pointer jumps erratically

Checkpoint Trouble Cause Countermeasure

Replace the vehicle speed
sensor, or repair an open
circuit in the circuit or a poor
connection at the connectors Vehicle speed sensor
malfunction, or open circuit or
poor connector contact

NG


Replace the meter assembly

Use meter tester to check the
speedometer function

Speedometer malfunction

NG
OK
Check the vehicle speed
sensor output by using the
oscilloscope





Inspection of a Waveform by Oscilloscope
(Reference)


RTW 780SH000101

1. Connect a resistance of 1.3 to 5k ohm (1.4W or more)
between the harness side connectors 40
B23 and 16

B24 of the meter.

2. Install a speedometer tester.
3. Turn on the starter SW .



RTW 580SH002201

4. Check the waveform at the time when the vehicle speed is
at 60km/h.



4. Trip odometer does not reset


Replace the meter assembly

Faulty reset mechanism

NG
Check at other kilometer
figures given by meter tester
(Reset should be made to
zero kilometer)


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ELECTRICAL-BODY AND CHASSIS 8A-345
TACHOMETER
1. Meter pointer fluctuates
(May be wide fluctuation)


Replace the meter assembly

Tachometer malfunction

NG

Use a meter tester to check
the tachometer function




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8A-346 ELECTRICAL-BODY AND CHASSIS
TEMPERATURE GAUGE AND THERMO UNIT (4JA1T(L), 4JH1-TC, C24SE)
1. No temperature indicates at all

Checkpoint Trouble Cause Countermeasure


Replace the thermo unit

Thermo unit malfunction

NG


Replace the case baseboard
assy

Gauge function
1. Disconnect the unit connector then connect
3.4W bulb to wire harness
side with ground
2. Check indicating point when starter SW . is ON
position (Temperature
should indicate)

Gauge malfunction


Repair open circuit or
connector contact
Continuity between 1 E19
(C24SE : 1
E65 ) and 16
B23 (C24SE : 13 B24 )


Open circuit or poor connector
contact

NG
NG
OK
OK
Thermo unit continuity
between connector 1
E19
(C24SE : 1
E65 ) and the
ground



2. Temperature gauge incorrect readings in all ranges


Replace the thermo unit

Thermo unit malfunction

NG

Thermo unit resistance
between connector 1
E19
(C24SE: 1
E65 ) and the
ground when disconnecting
the connector (Specified
resistance should indicate)



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ELECTRICAL-BODY AND CHASSIS 8A-347
ENGINE COOLANT TEMPERATURE GAUGE (4JJ1-TC/4JK1-TC)
Refer to “Inspection and Repair” in this Manual for a detailed description of the coolant temperature gauge self-
diagnosis procedure.

1. No engine coolant temperature indicates at all

Checkpoint Trouble Cause Countermeasure


Replace the engine coolant
temperature sensor

Engine coolant temperature
sensor malfunction

NG


Replace the meter assembly

Gauge function
1. Disconnect the sensor connector then connect
3.4W bulb to wire harness
side with ground
2. Check indicating point when starter SW . is ON
position (Temperature
should indicate)

Gauge malfunction


Repair open circuit or
connector contact

Continuity between 3
E41
and 16
B23


Open circuit or poor connector
contact

NG
NG
OK
OK
Engine coolant temperature
sensor continuity between
connector 3
E41 and the
ground



2. Engine coolant temperature gauge incorrect readings in all ranges


Replace the sensor

The sensor malfunction

NG

Engine coolant temperature
sensor resistance between
connector 3
E41 and the
ground when disconnecting
the connector (Specified
resistance should indicate)


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8A-348 ELECTRICAL-BODY AND CHASSIS
TEMPERATURE GAUGE AND THERMO UNIT (HFV6)
1. No temperature indicates at all

Checkpoint Trouble Cause Countermeasure


Replace the thermo unit

Thermo unit malfunction

NG


Replace the case baseboard
assy

Gauge function
1. Disconnect the unit connector then connect
3.4W bulb to wire harness
side with ground
2. Check indicating point when starter SW . is ON
position (Temperature
should indicate)

Gauge malfunction


Repair open circuit or
connector contact

Continuity between 8 B96
and 16
B23


Open circuit or poor connector
contact

NG
NG
OK
OK
PIM (Thermo unit) continuity
between connector 8
B96
and the ground




2. Temperature gauge incorrect readings in all ranges


Replace the thermo unit

Thermo unit malfunction

NG
PIM (Thermo unit) resistance
between connector 8
B96
and the ground when
disconnecting the connector
(Specified resistance should
indicate)




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ELECTRICAL-BODY AND CHASSIS 8A-349
FUEL GAUGE AND FUEL TANK UNIT (C24SE, 4JJA1T(L), 4JH1-TC, 4JJ1-TC/4JK1-TC)
1. No fuel level indicates at all

Checkpoint Trouble Cause Countermeasure


Replace the tank unit

Open circuit inside the tank
unit

NG
Thermo unit malfunction

Replace the case baseboard
assy

Fuel gauge function
1. Disconnect the tank unit connector then connect
3.4W bulb to wire harness
side
2. Check indicating point when starter SW . is ON
position (Fuel level should
indicate)

Gauge malfunction


Repair open circuit or
connector contact
Continuity between
connectors 17
B23 (C24SE :
14
B24 ) and 3
F2


Open circuit or poor connector
contact

NG
NG
OK
OK

Tank unit continuity between
connector 3
F2 and ground




2. Fuel gauge gives incorrect readings in all ranges

Replace the tank unitTank unit malfunction
NG
Tank unit resistance position
with the float at checking
points (Specified resistance
should indicate)


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8A-350 ELECTRICAL-BODY AND CHASSIS
FUEL GAUGE AND FUEL TANK UNIT (HFV6)
1. No fuel level indicates at all

Checkpoint Trouble Cause Countermeasure


Replace the tank unit

Open circuit inside the tank
unit

NG
Thermo unit malfunction

Replace the case baseboard
assy

Fuel gauge function
1. Disconnect the tank unit connector then connect
3.4W bulb to wire harness
side
2. Check indicating point when starter SW . is ON
position (Fuel level should
indicate)

Gauge malfunction


Repair open circuit or
connector contact
Continuity between
connectors 17
B23 and 17

B96

Open circuit or poor connector
contact

NG
NG
OK
OK
PIM (Tank unit) continuity
between connector 17
B96
and ground



2. Fuel gauge gives incorrect readings in all ranges

Replace the tank unitTank unit malfunction
NG
Tank unit resistance position
with the float at checking
points (Specified resistance
should indicate)



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ELECTRICAL-BODY AND CHASSIS 8A-351
WARNING AND INDICATOR LIGHT
1. When the parking brake lever is pulled, the brake indicator light does not light up

Checkpoint Trouble Cause Countermeasure


Replace or reinstall the bulb

Bulb burned out or loose
contact

NG

Adjust or replace the parking
brake SW .

Parking brake SW . installation
position and function

Incorrect SW . adjustment or
poor SW . point contact

Continuity between the
parking brake SW . connector
1
C39 (stick type), 1 R4
(lev er type), and 4
B23
(C24SE : 9
B23 )

Repair open circuit or
connector contact

Open circuit or poor connector
contact

NG
NG
OK
OK

Brake indicator light bulb
continuity

NG
OK
Continuity between the
parking brake SW . connector
1
C39 (stick type), 1 R4
(lev er type) and the ground
when the parking brake is
operated

Replace the parking brake
SW .

Parking brake SW .
malfunction





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8A-352 ELECTRICAL-BODY AND CHASSIS
2. When the parking brake lever is released, the indicator light does not go off

Checkpoint Trouble Cause Countermeasure

Adjust the SW . installation
position or replace the parking
brake SW . Incorrect the parking brake
SW . adjustment or parking
brake SW . faulty

NG
Thermo unit malfunction
Replace the brake fluid level
SW ., or repair a short circuit
between the parking brake
SW . connector 1
C39,
1
R4 and 4 B23 (C24SE :
9
B23 ) or the brake fluid
level SW . connector 2
C37
and 4
B23 (C24SE : 9

B23 )
Check to see if the indicator
light goes off when the parking
brake SW . connector 1
C39
(stick type), 1
R4 (lever
type) is disconnected
Brake fluid level SW . faulty or
short circuit

NG
OK

Parking brake SW . installation
position and function



3. Oil pressure warning light does not go off while engine is running


Refer to ENGINE Section

Refer to ENGINE Section

NG Thermo unit malfunction
Check to see the warning light
goes off when the oil pressure
SW . connector
1
E1 is disconnected or
when the PIM (Oil pressure)
connector 6
B96 (HFV6) is
disconnected
Repair a short circuit between
1
E1 and 39 B23
(C24SE : 17
B24) or 6
B96 and 39 B23 (HFV6)

Short circuit

NG
OK

Replace the oil pressure SW .

Continuity between the oil
pressure SW . connector
1
E1 (HFV6 : 6 B96 )and
the body ground when the
engine is operating

Oil pressure SW . faulty

NG
OK

Engine oil pressure





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