Navistar MaxxForce DT Diagnostic Manual page 109

Step
5 Determine if removed aftertreatment system components
need to be cleaned see DPF and DOC reuse guidelines
page 159.
Based on DPF and DOC Re-Use Guidelines, do any of
the removed aftertreatment system components need to
be cleaned?
Step
6 Determine root cause of exhaust system contamination.
(See Engine Symptoms Diagnostics section in Engine
Diagnostic Manual.)
Step
7 Diesel Particulate Filter ( DPF) Snap Acceleration Test
(Quick Test). This procedure checks the DPF for cracks
or internal damage without removing the DPF from the
vehicle and is used to test basic functionality of the DPF.
This is to be done prior to removing the DPF.
1. The transmission must be in neutral and the
parking brake applied.
2. Start and idle the engine.
3. Rapidly snap the accelerator pedal from idle
to full throttle. This can be performed multiple
times.
4. During the engine accelerations, visually
check for a heavy black smoke exiting the
exhaust pipe.
Is black smoke visible?
Action
Action
Action
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DIAGNOSTIC MANUAL
Decision
Yes: Clean components using
appropriate cleaning equipment. After
cleaning procedure is complete, install
components and go to step 7.
No: Install removed aftertreatment
system components, and go to step 7.
Decision
After repairs are complete, go to step 8.
Decision
Yes: Go to symptom 5 (Heavy Duty):
Black smoke page 113.
No: Go to step 8
105