Isuzu N 2008 Series Workshop Manual page 37

1A-34 Engine Control System (4JJ1)
Step
1. Review the following symptoms.
2. Refer to the applicable symptom diagnostic
table:
• Hard Start
• Rough, Unstable, or Incorrect Idle and
Stalling
• High Idle Speed
• Cuts Out
• Surges
• Lack
14
Sponginess
• Hesitation, Sag, Stumble
• Abnormal Combustion Noise
• Poor Fuel Economy
• Excessive Smoke (Black Smoke)
• Excessive Smoke (White Smoke)
• DPD
Frequently
• DPD System Regeneration Long Time
Did you find and correct the condition?
Diagnostic System Check - Engine Controls (Except Euro 4 Specification)
Step
Install a scan tool.
1
Does the scan tool turn ON?
1. Turn ON the ignition, with the engine OFF.
2. Attempt to establish communication with the
listed control modules.
• ECM
• Transmission
(Smoother only)
• Hill start aid (HSA) control unit (If so
2
equipped)
• Supplemental restraint system (SRS)
control unit (If so equipped)
• Immobilizer control unit (ICU) (If so
equipped)
Does the scan tool communicate with all the listed
control modules?
Notice: If an immobilizer system is active the ECM
will disable the fuel injection causing the engine to
stall immediately after starting and energize the
3
starter cut relay to disable cranking. Attempt to
crank the engine.
Does the engine crank?
Attempt to start the engine.
4
Does the engine start and idle?
Does the scan tool display ECM DTCs P0633,
P161B or U0167?
5
Action
of Power, Sluggishness,
System Manual Regeneration
Action
control module
Value(s)
or
—
Value(s)
—
(TCM)
—
—
—
—
Yes
Go to Intermittent
System OK
Yes
Go to Scan Tool
Go to Step 2 Does Not Power Up
Go to Scan Tool
Communicate with
Go to Step 3 Keyword Device
Go to Step 4
Cranks but Does
Go to Step 6
Problem is relating
to starting system.
Refer to Starting
Go to Applicable System in Section
DTC 1E Engine Electrical
No
Conditions
No
Does Not
Go to Step 5
Go to Engine
Not Run