DIAGNOSTICMANUAL
Step
ActionDecision
6
DieselParticulateFilter(DPF)SnapAccelerationT est(Quick
Test).ThisprocedurecheckstheDPFforcracksorinternal
damagewithoutremovingtheDPFfromthevehicleandisused
totestbasicfunctionalityofthedieselparticulatelter.Thisisto
bedonepriortoremovingtheDPF .
1.Thetransmissionmustbeinneutralandtheparking
brakeapplied.
2.Startandidletheengine.
3.Rapidlysnaptheacceleratorpedalfromidletofull
throttle.Thiscanbeperformedmultipletimes.
4.Duringtheengineaccelerations,visuallycheckfora
heavyblacksmokeexitingtheexhaustpipe.
Isblacksmokevisible?
Yes:GotoSymptom5
(MediumDuty):Blacksmoke
page44.
No:Gotostep11
Step
ActionDecision
7
DetermineifDieselParticulateFilter(DPF),Pre-DieselOxidation
Catalyst(PDOC),andDieselOxidationCatalyst(DOC)are
contaminated.RemovetheDPF ,PDOC,andDOC(seeExhaust
SystemServiceManual),andcheckforsignsoflubeoiland
coolantcontamination.
NOTE–Ablackstainingintheexhausttailpipecanoccuron
applicationsthatexperiencehighidletimes.Thisisnormal
andtheDPFshouldNOTbereplaced.
AretheDPF ,PDOC,orDOCcontaminated?
Yes:Gotostep8
No:Gotostep9
Step
ActionDecision
8
DetermineifDPF ,DOC,andPDOCarereusableseeDPFand
DOCreuseguidelinespage159.
BasedonDPFandDOCRe-UseGuidelines,aretheDPF ,DOC,
andPDOCreusable?
Yes:Gotostep10
No:Replacefailed
component(s).Afterrepairs
arecomplete,gotostep10.
26
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