Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1394

ELECTRICAL-BODY AND CHASSIS  8-141

3. Speedometer needle 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 speedometer

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

1. Connect a resistance of 1.3 to 5k ohm (1.4W or more) between the harness side connectors 2 

B-24

 and 9

B-23

 of the meter.

2. Install a speedometer tester.

2. Turn on the starter SW.

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

4. Trip odometer does not reset

Replace the speedometer

Faulty reset mechanism or

worn gear

NG

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

8-142  ELECTRICAL-BODY AND CHASSIS

TACHOMETER

1. Tachometer does not function when engine is running

Checkpoint

Trouble Cause

Countermeasure

Replace the tacho sensor, or

repair open circuit or

connector contact

Tacho sensor malfunction, or

open circuit or poor connector

contact

NG

Replace the tachometer

Tachometer function

Tachometer malfunction

NG

OK

Pulse between connector

B-24

 and the ground when

engine is running (Should be
pulse present)

2. Meter needle fluctuates

(May be wide fluctuation)

Replace the tachometer

Tachometer malfunction

NG

Use a meter tester to check

the tachometer function

ELECTRICAL-BODY AND CHASSIS  8-143

TEMPERATURE GAUGE AND THERMO UNIT

1. No temperature indicates at all

Checkpoint

Trouble Cause

Countermeasure

Replace the thermo unit

Thermo unit malfunction

NG

Replace the temperature

gauge

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 

E-8

and 6 

B-24

Open circuit or poor connector

contact

NG

NG

OK

OK

Thermo unit continuity
between connector 

E-8

 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 

E-8

and the ground when
disconnecting the connector
(Specified resistance should
indicate)

8-144  ELECTRICAL-BODY AND CHASSIS

FUEL GAUGE AND FUEL TANK UNIT

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 fuel gauge

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 11 

B-23

 and 1

F-1

Open circuit or poor connector

contact

NG

NG

OK

OK

Tank unit continuity between

connector 1 

F-1

 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)