Frequently - Isuzu N 2008 Series Workshop Manual

DPD System Manual Regeneration Frequently
Checks
Definition:
The manual regeneration is frequently requested to the driver by blinking the DPD amber lamp. Or, it is frequently requested as
compared with before. (The automatic regeneration cannot be completed frequently.)
Preliminary Checks
Sensor Checks
Fuel System Checks
• Inspect the fuel quality.
• Inspect the engine oil level and quality.
• Inspect the odometer is correctly operated.
• If an excessive black smoke is present, refer to Excessive Smoke (Black Smoke)
chart in symptom diagnostic table.
• An excessive ash accumulation in the DPD filter.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Inspect the driving habits/ conditions of the owner for the following conditions. Suggest
to the owner to use the selectable regeneration as necessary:
In normal operation;
• Is the idling time too long?
• Is the driving at slow vehicle speed too often?
• Is the driving at long downhill?
• Is a small cargo delivery truck or a garbage truck?
• Is the PTO operating time too long?
In regeneration;
• Is the idling time too long?
• Is the driving at slow vehicle speed too often?
• Is the PTO operating too often and/ or for a long time?
• Is the engine runtime short?
• Is the vehicle runtime short?
• Is the accelerator pedal ON and OFF too often?
Inspect the engine control sensors relating to the DPD system control for the following
conditions. Refer to Scan Tool Data List in this section.
• Misrouted or disconnected exhaust differential pressure hoses or pipes.
Notice: There is installation directionality in the exhaust differential pressure hoses.
Refer to Exhaust System in Section 1G Engine Exhaust.
• Plugged, crushed or kinked exhaust differential pressure hoses or pipes.
• Dislocated or inclined exhaust differential pressure sensor. Refer to Exhaust System
in Section 1G Engine Exhaust.
• Physical damage of the exhaust differential pressure sensor.
• Any contamination or objects that block the exhaust differential pressure sensor
port.
• Observe the Exhausts Differential Pressure parameter for a skewed or slow exhaust
differential pressure sensor.
• Skewed or slow exhaust temperature sensors. Use the Temperature vs. Resistance
table to test the exhaust temperature sensor at various temperature levels to
evaluate the possibility or a skewed sensor.
• Observe the MAF parameter for a skewed or slow MAF sensor.
• Observe the Boost Pressure and Barometric Pressure (BARO) with ignition ON and
engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other.
Inspect the fuel system problem. Refer to Fuel System Check chart and appropriate
procedure in Section 1D Engine Fuel.
Engine Control System (4JJ1)
Action
1A-345