Isuzu 4HL1 Workshop Manual page 239

Step
Replace the intermediate connector.
6
Is the action complete?
Check the common 1 injector drive circuit
(intermediate connector to injector) for open
wiring.
1. Disconnect the injector side connector
from the intermediate connector.
2. Disconnect harnesses from the cylinder 1
7
or 4 injector.
3. Measure the resistance between injector
terminal and connector pin as well as
between connector pins.
Was the resistance within range?
Repair or replace the faulty harness.
8
Is the action complete?
Measure the resistance between injector
terminals (resistance of coil) for cylinders 1
9
and 4.
Was the resistance within range?
Repair or replace the faulty injector(s).
10
Is the action complete?
Check DTC277 will not be set again.
1. Restore the vehicle.
2. Using Tech 2, clear the DTC.
11
3. Bleed the air from the fuel system.
4. Perform test run and review the DTC.
Is DTC277 detected?
Review the DTC.
1. Restore the vehicle.
2. Using Tech 2, clear the DTC.
12
3. Perform test run and review the DTC.
Is DTC277 detected?
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
13
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Check DTC277 will not be set again.
1. Using Tech 2, clear the DTC.
14
2. Perform test run and review the DTC.
Is DTC277 detected?
Action
Engine Control System 1A-237
Value(s)
—
Go to Step 14
Cylinder 1-
pins 1:
0 Ω
Cylinder 4-
pins 4:
0 Ω
Pins 1-4: ∞ Ω
Go to Step 9
Verify repair and
—
go to Step 14
0.4 Ω
Go to Step 12
—
Go to Step 11
—
Refer to
Diagnostic Aids
and go to Step 2
—
Go to Step 13
—
Verify repair and
go to Step 14
—
Refer to
Diagnostic Aids
and go to Step 2
Yes No
Go to Step 8
Go to Step 10
Repair is
complete
Refer to
Diagnostic Aids
Repair is
complete
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—
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