Isuzu 2008MY N Series Workshop Manual page 71

1A-68 Engine Control System (4HK1)
Step
1. Inspect the turbocharger assembly for the
following conditions:
• Physical damage of turbocharger
• Turbocharger
damaged
• Physical damage of VNT actuator &
5
sensor
• Loose or improper installation of VNT
actuator & sensor
2. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the VNT actuator & sensor
harness connector.
3. Connect a test lamp between the each
solenoid circuit (pins 6, 7 and 8 of E-2) and a
known good ground.
4. Turn ON the ignition, with the engine OFF.
6
Notice: Ignition switch must be cycled when
the test lamp is probed to other positions.
Is there circuit which did not illuminate, or
continuously illuminate the test lamp (note
that the test lamp illuminate then go out
normally)?
1. Test the solenoid circuit between the VNT
control module (pins 10, 11 and 12 of E-4) and
the actuator & sensor (pins 6, 7 and 8 of E-2)
for a short circuit each other.
7
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the solenoid circuits (which ever circuit
did not illuminate, or continuously illuminate at
Step 6) between the VNT control module (pins
10, 11 and 12 of E-4) and the actuator &
sensor (pins 6, 7 and 8 of E-2) for the
following conditions:
• An open circuit
8
• A short to ground
• A short to battery or ignition voltage
• A short to the position sensor circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Connect a DMM between the position sensor
reference voltage circuit (pin 1 of E-2) and a
known good ground.
9
3. Turn ON the ignition, with the engine OFF.
Is the DMM voltage within the specified
value?
Action
nozzle control linkage
Value(s)
—
Go to Step 20
—
Go to Step 8
—
Go to Step 20
—
Go to Step 20
8.0 to 10.0
volts
Go to Step 10
Yes No
Go to Step 6
Go to Step 7
Go to Step 16
Go to Step 17
Go to Step 13