Isuzu 2008MY N Series Workshop Manual page 324

Step
1. Perform the Intake Throttle Solenoid Control
with a scan tool several times.
2. Command the Desired Intake Throttle Position
Increase and Decrease while observing the
6
Intake Throttle Position.
Does the Intake Throttle Position parameter
follow within the specified value quick
enough?
1. Remove the EGR valve assembly from the
engine.
2. Inspect the EGR valve for the following
conditions:
• Restricted
materials
7
• Excessive deposits at valve
• Bent valve shaft
3. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the EGR valve harness connector.
3. Inspect for
connections and corrosion at the harness
connector of the EGR valve (pins 1, 2, 3, 4, 5,
6, 7 and 8 of E-15).
4. Disconnect the ECM harness connector.
5. Inspect for
8
connections and corrosion at the harness
connector of the ECM (pins 87, 93, 94, 99,
101 103, 110 and 111 of E-12).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as
necessary.
Did you find and correct the condition?
1. Remove the intake duct that is connected to
the intake throttle valve.
2. Inspect the intake throttle valve for the
following conditions:
• Restricted intake throttle valve by foreign
materials
• Excessive deposits at throttle bore
9
• Bent butterfly valve
Notice: Replace the intake throttle valve is
there is any sticking
3. Repair or replace as necessary.
Did you find and correct the condition?
Action
EGR valve by foreign
an intermittent, for
an intermittent, for
Engine Control System (4HK1)
Value(s)
± 5%
—
poor
poor
—
—
Yes
System OK Go to Step 9
Go to Step 13 Go to Step 8
Go to Step 13 Go to Step 11
Go to Step 13 Go to Step 10
1A-321
No