Isuzu 2008MY N Series Workshop Manual page 40

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)
2
• Hill start aid (HSA) control unit (If so
equipped)
• Supplemental restraint system (SRS)
control unit (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
Select the DTC display function for the following
control modules:
• ECM
• TCM (Smoother only)
6 • EHCU (If so equipped)
• HSA control unit (If so equipped)
• SRS control unit (If so equipped)
Does the scan tool display any DTCs?
Does the scan tool display DTCs which begin
with U or other control module communication
7
fault DTCs?
Does the scan tool display ECM DTCs P0601,
8
P0602, P0604, P0606, P060B or P1621?
Does the scan tool display ECM DTC P0563?
9
Is there any other code in any controller that
10
has not been diagnosed?
Is the customer's
transmission?
11
Action
control module (TCM)
concern with
Engine Control System (4HK1)
Value(s)
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the
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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
Go to Step 7
Go to Applicable
DTC
Go to Applicable
DTC
Go to Applicable
DTC
Go to Applicable
DTC
Go to Diagnostic
System Check -
Transmission
Controls in Setion
5A Transmission
Control System
1A-37
No
Does Not
Go to Step 5
Go to Engine
Not Run
Go to Step 11
Go to Step 8
Go to Step 9
Go to Step 10
Go to Step 11
Go to Step 12