Isuzu KB P190. Manual — part 1321

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)

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)

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)

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 unit

Tank unit malfunction

NG

Tank unit resistance position
with the float at checking
points (Specified resistance
should indicate)