Navistar MaxxForce 15 - 9.5. SYMPTOM 4 (HEAVY DUTY): SPN 3719 AND OTHER ACTIVE FAULT CODES

DIAGNOSTICMANUAL
Step
ActionDecision
8CVerifyaftertreatmentsystemisfreeofrestrictions.Using
EST,usetheplaybackfeatureandgraphthefollowing
signalvaluesfromLugDownTest:
SignalValues:
•EngineSpeed
•Turbocharger1TurbineOutletPressure(TC1TOP)
ComparesnapshottoGraph4andassociatedGraph
Analysispage126.
IsTC1TOPsignaloperatingasperGraph4Graph
Analysis?
Yes:Gotostep8D
No:RepairTC1TOPissue(See
ElectronicControlSystemsDiagnostics
inEngineDiagnosticManual).After
repairsarecomplete,retestfororiginal
problem.
Step
ActionDecision
8D
CheckforanIntakeManifoldPressure(IMP)issue.Usethe
playbackfeatureinServiceMaxx™,andgraphthefollowing
signalvaluesfromLugDownTest:
SignalValues:
•EngineSpeed
•IntakeManifoldPressure(IMP)
•AcceleratorPedalPosition1(APP1)
•VehicleSpeed
ComparesnapshottoGraph5andassociatedGraph
Analysispage127.
IsIMPoperatingasperGraph5GraphAnalysis?
Yes:Gotostep9
No:DiagnoseandrepairIMPissue
(SeePerformanceDiagnosticssection
inEngineDiagnosticManual).After
repairsarecomplete,retestfororiginal
problem.
100
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