Isuzu 2008MY N Series Workshop Manual page 292

Step
1. Inspect the following for possible causes of
high exhaust differential pressure.
• 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
• Physical
differential pressure sensor
3
• Any contamination or objects that block
the exhaust differential pressure sensor
port
• Skewed or slow exhaust differential
pressure sensor
• Exhaust gas leakage from the exhaust
differential pressure hoses or pipes
• Restricted or collapsed exhaust system
• Modified exhaust system
2. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the exhaust differential pressure
sensor harness connector.
3. Inspect for
connections and corrosion at the harness
connector of the exhaust differential pressure
sensor (pins 1, 2 and 3 of J-33).
4. Disconnect the ECM harness connector.
5. Inspect for
4
connections and corrosion at the harness
connector of the ECM (pins 67, 79 and 80 of
J-14).
6. Test each sensor circuit between the ECM and
the exhaust differential pressure sensor for
high resistance.
7. Repair the connection(s) or circuit(s) as
necessary.
Did you find and correct the condition?
Important: Clear the DTC and the DPD Status in
the ECM must be reset when the DPD filter is
replaced.
5
Replace the DPD filter. Refer to Exhaust System in
Section 1G Engine Exhaust.
Did you complete the replacement?
Action
or disconnected exhaust
There is installation
hoses. Refer to Exhaust
damage of the exhaust
an intermittent, for
an intermittent, for
Engine Control System (4HK1)
Value(s)
—
poor
poor
—
—
Yes
Go to Step 6 Go to Step 4
Go to Step 6 Go to Step 5
Go to Step 8
1A-289
No
—