Isuzu N 2008 Series Workshop Manual page 351

1A-348 Engine Control System (4JJ1)
Checks
Air Intake System Checks
Exhaust System Checks
Additional Checks
Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• Modified air induction system.
• A restriction or damaged or any contamination or objects that block at MAF sensor.
• A worn or damaged turbocharger turbine wheel, shaft or compressor wheel. Refer to
Turbocharger Assembly in Section 1J Engine Induction.
Inspect the exhaust system for the following conditions. Refer to Exhaust System in
Section 1G Engine Exhaust.
• An exhaust system gasket that is missing or damaged.
• Exhaust gas leakage from the exhaust pipe, gasket, DPD assembly, exhaust
temperature sensor(s) or exhaust 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.
• DPD filter for damage, cracks, melt or excessive deposits.
• Oxygen catalyst for damage, cracks, melt or excessive deposits.
• If an excessive white smoke is present while regeneration event, a deteriorated or
damaged oxygen catalyst is suspected.
• Inspect for an engine overheat condition. Refer to Cooling System in Section 1C
Engine Cooling.
• Inspect the A/C operation.
Action