DIAGNOSTICMANUAL
Step
ActionDecision
7
DieselParticulateFilter(DPF)SnapAccelerationT est(QuickT est).
ThisprocedurecheckstheDPFforcracksorinternaldamage
withoutremovingtheDPFfromthevehicleandisusedtotestbasic
functionalityofthedieselparticulatelter.Thisistobedonepriorto
removingtheDPF .
1.Thetransmissionmustbeinneutralandtheparking
brakeapplied.
2.Startandidletheengine.
3.Rapidlysnaptheacceleratorpedalfromidletofull
throttle.Thiscanbeperformedmultipletimes.
4.Duringtheengineaccelerations,visuallycheckfora
heavyblacksmokeexitingtheexhaustpipe.
Isblacksmokevisible?
Yes:GotoSymptom5
(MediumDuty):Blacksmoke
page44.
No:Gotostep12
Step
ActionDecision
8
DetermineifDieselParticulateFilter(DPF),Pre-DieselOxidation
Catalyst(PDOC),andDieselOxidationCatalyst(DOC)are
contaminated.RemovetheDPF ,PDOC,andDOC(seeExhaust
SystemServiceManual),andcheckforsignsoflubeoilandcoolant
contamination.
NOTE–Ablackstainingintheexhausttailpipecanoccuron
applicationsthatexperiencehighidletimes.Thisisnormaland
theDPFshouldNOTbereplaced.
AretheDPF ,PDOC,orDOCcontaminated?
Yes:Gotostep9
No:Gotostep10
Step
ActionDecision
9
DetermineifDPF,DOC,andPDOCarereusableseeDPFandDOC
reuseguidelinespage159.
BasedonDPFandDOCRe-UseGuidelines,aretheDPF ,DOC,
andPDOCreusable?
Yes:Gotostep11
No:Replacefailed
component(s).Afterrepairs
arecomplete,gotostep11.
36
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