Default Matrix Table - Isuzu 4HL1 Workshop Manual

1A-250 Engine Control System
Step
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
5
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Check DTC543 will not be set again.
1. Using Tech 2, clear the DTC.
6
2. Perform test run and review the DTC.
Is DTC543 detected?

Default Matrix Table

Symptom
No cranking
No initial combustion
Poor startability at ordinary temperature The engine runs after long startup process.
Poor startability at low temperature
Hunting / instable idling
High idle speed
Low idle speed
Engine stall before warm-up
Engine stall after warm-up
Short power / poor response / stumble
Black smoke
White smoke
Large engine vibration
Unusual sound
Symptom Diagnosis Chart
* Using Symptom Diagnosis Chart 1, cross-check the
symptom (column) and item number and diagnose the
current fault according to the procedure in Symptom
Diagnosis Chart 2.
Action
When the starter switch is moved to the position "ST", the starter is not
activated.
The engine provides cranking but does not run.
The engine shows good startability at ordinary temperature but it takes
long time to start at low temperature.
The idle speed is instable or varying. In the serious case, the engine or
vehicle may vibrate, resulting in occasional stall/stop.
The idle speed is much higher than the specified level.
The idle speed is much lower than the specified level.
The engine frequently stalls before warm-up.
The engine frequently stalls after warm-up.
The engine output is less than the desired level and even pressing the
accelerator pedal extensively will hardly or not increase the engine
speed.
Lots of black smokes are generated on the road test.
Lots of white smokes are generated on the road test.
The engine generates unusual vibrations as high as the driver feel them
in the cab.
Unusual sounds such as beep or rattling sounds are generated.
Value(s) Yes
—
Verify repair and
go to Step 6
—
Refer to
Diagnostic Aids
and go to Step 2
Definitions
No
—
Repair is
complete