Isuzu 4HL1 Workshop Manual page 51

Step
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
9
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Observe the CHECK ENGINE lamp for
operation.
1. Short DLC (Data Link Connector) pins 4
and 6 and turn on the diagnostic switch.
10
2. Starter switch "ON", and observe the
CHECK ENGINE lamp.
Does the CHECK ENGINE lamp blink?
Using Tech 2, check DTC.
11
Is DTC detected?
Start the engine.
12
Does the engine start and continue running?
1. Using Tech 2, display engine data.
2. Compare engine data to Tech 2 typical
values.
13
Do engine data almost agree with typical
values?
Action
Engine Control System 1A-49
Value(s) Yes
—
Go to Step 4
—
Go to Step 11
Go to the
— appropriate DTC
Chart.
—
Go to Step 13
—
The OBD system
is in normal
condition
No
—
Refer to
"Unblinking
CHECK ENGINE
Lamp Check" and
go to Step 11
Go to Step 12
Refer to
"Symptom
Diagnosis Chart"
and go to Step 13
Refer to "Test
Description"