Isuzu NHR 4J Series, Workshop Manual

Page: 378 / 406

QOSIII PREHEATING SYSTEM 6D7 – 5
Inspection on QOSIII System Operation
I
Inspection on Quick Heating Operation
1. Disconnect thermo-sensor connection on the
thermostat housing.
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following items with starter switch set to
ON position (but do not start the engine).
1) The glow indicator shall light for 1 ~ 6 sec.
2) The circuit tester shall indicate power supply voltage
for 9 ~ 13 sec.
• If above specifications are not satisfied, inspect wire
harness, glow relay and thermo-sensor. If satisfied,
inspect glow plug.
II
Inspection on Quick Heating Afterglow Operation
1. Disconnect thermo-sensor connection on the
thermostat housing.
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following item with start the engine.
1) The circuit tester shall indicate power supply voltage
for about 5 seconds.
• If above specification is not satisfied, inspect battery
voltage, engine earth, wire harness and starter switch
"st" signal to control unit.
If satisfied, inspect wiring harness, engine earth and
starter switch.
III
Inspection on Afterglow Operation
1. Disconnect thermo-sensor connection on the
thermostat housing.
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