Isuzu 2008MY N Series Workshop Manual page 341

1A-338 Engine Control System (4HK1)
Step
1. Inspect the following conditions:
• Misrouted
differential pressure hoses or pipes
Important:
directionality in the exhaust differential
pressure
System in Section 1G Engine Exhaust .
• Plugged, crushed or kinked exhaust
differential pressure hoses or pipes
• Dislocated or inclined exhaust differential
pressure
System in Section 1G Engine Exhaust .
• Physical
differential pressure sensor
• Any contamination or objects that block
the exhaust differential pressure sensor
port
• Skewed or slow exhaust differential
pressure sensor
• An exhaust system gasket that is missing
or damaged
4
• Exhaust gas leakage from the exhaust
pipe, gasket, DPD assembly, exhaust
temperature
differential pressure hoses or pipes
• Modified exhaust system
• Exhaust throttle valve or exhaust brake
valve for stuck condition. Refer to
Exhaust System in Section 1G Engine
Exhaust.
• Skewed or slow exhaust temperature
sensors
• Restricted air cleaner element, restricted
or collapsed air tubing between the air
cleaner and the intake manifold
• Modified air induction
• Any air induction leak
• Any contamination or objects that block
the mass air flow (MAF) sensor inlet
• Skewed or slow MAF sensor
2. Repair or replace as necessary.
Did you find and correct the condition?
Start the engine and let idle for 30 seconds.
5
Does the DPD lamp or "PUSH DPD SWITCH"
indicator blink?
Perform the DPD manual regeneration by pressing
the DPD switch.
6
Does the regeneration start?
Observe the DPD Accumulation Status and DPD
Distance Status with a scan tool, and plot both
7
readings on the DPD status table.
Is the intersected range located in A or B?
Action
or disconnected exhaust
There is installation
hoses. Refer to Exhaust
sensor. Refer to Exhaust
damage of the exhaust
sensor(s) or exhaust
Value(s) Yes
—
Go to Step 14
—
Go to Step 6
—
Go to Step 10
—
Go to Step 8
No
Go to Step 5
Go to Step 7
ECM is not allowing
the DPD
regeneration
control. Refer to
Test Description and
DTC List
Go to Step 9